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In retrospect it thus appears that two separate series of influenza epidemics occurred during the year. The belief that it was the same disease in each instance is supported by the fact that many men of the Navy who had influenza in the spring or summer of 1918, while in European waters, escaped during the later epidemics both in Europe and in the United States. The British Grand Fleet experienced the same thing; with few exceptions those men who contracted influenza in May and June were not attacked during the more fatal epidemics in October, November, and December. The conclusion is that mild attacks earlier in the year, as a rule, conferred immunity against the more fatal type of the disease which prevailed subsequently.

In fact, there is good ground for the view that many at least of the sporadic cases diagnosed as grippe during interpandemic years are really influenza and that this disease is quite as much an entity as measles and other well-recognized communicable diseases. This

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Chart No. 4

is perhaps worth mentioning in passing because of the conflict of opinion which has arisen during the past year.

Pandemics of influenza have been occurring periodically for centuries. If the 1918 pandemic is a criterion, they do not appear suddenly but develop gradually, the incidence and prevalence of influenza, either in recognizable form or under diagnosis of various respiratory diseases, increasing for a year or two in many countries to such an extent as to be revealed plainly in annual mortality statistics. Presently, widespread fleeting epidemics of short duration, associated with low case-fatality rates, perhaps, and as a rule bearing little obvious relation to one another at the time, occur in many countries several months previous to the appearance of the disease in the type where starting in some part of the world one epidemic after another, each manifestly related to the one in the country or State just previously visited, spread progressively much after the fashion of prairie fires, over the entire inhabited portions of the globe, but few communities here and there escaping. The rate of spread during the autumn months of 1918 was so rapid indeed as to revive the old discussion as to the possibility of air-borne infection, but a review of the pandemic to date leads to a conviction that the disease can not spread faster than human beings travel.

Previous Pandemics of Influenza.

The ordinates, which represent the annual exact or estimated rates, if smoothed by either free-hand drawing or by the procedure of "moving averages," would apparently result in great interpandemic curves of the hyperbolic or parabolic types. From these figures and curves one may infer that a great pandemic of influenza does not occur in a single great wave, covering a course of a few weeks or months and then disappearing, but that the disease, as reflected by the death rates, prevails extensively through a term of years within which there occur two or more years of very high death rates from this cause, or distinct epidemics of the disease.

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The history of influenza records a severe epidemic in 1510, another in 1557-58, again in 1657-58, and in 1729. Severe epidemics apparently occurred in four different years between 1729 and 1743, inclusive--1729, 1733, 1737, and 1743. Another severe epidemic occurred in 1833 and the disease continued in unusual prevalence through 1848. High death rates were again recorded in four different years--1833, 1837, 1847, and 1848-49. The next period of high death rates, during which the pandemic of 1889-90 occurred, lasted until 1900 and included high mortality rates from influenza in practically every year of the period, but particularly in 1891, 1892, 1893, 1895, 1898, 1899, and 1900.

From a summary of the course of events presented by Sir Arthur Newsholme it appears that no epidemic occurred in 1901. In 1902 a small epidemic lasting from six to eight weeks occurred. There were no epidemics in 1903, 1904, or 1905. An epidemic of low magnitude and somewhat protracted duration occurred in December, 1906, and in January, 1907. In 1908 a smarter epidemic occurred, culminating in the ninth week of the year. A similar epidemic occurred in 1909, reaching its maximum in the twelfth week of the year. No epidemics occurred in 1910, 1911, or 1912. In 1913 an epidemic of low range occurred with maximum mortality in the twelfth week of the year. No epidemic occurred in 1914. In 1915 an epidemic similar to that of 1913 reached its height late in February. A considerable low-ranged increase of mortality was visible in the early part of 1916, followed by a relatively small epidemic, culminating in the last week of the year and terminating early in 1917.

The last great period of influenza began, perhaps, in 1916 and culminated in the pandemic of 1918. The great epidemics in England and Wales came approximately with periods of widespread diffusion of the disease throughout all Europe in the early centuries and throughout the whole Eastern Hemisphere, and, indeed, the whole world, ini the later centuries, the great epidemics, probably, all indicating pandemics.

Mortality statistics of the United States furnish but little evidence relating to the 1847-48 pandemic and even those covering the 1889-90 pandemic are so lacking in completeness for practically all States that satisfactory comparison can not be made with the statistics of 1918-19. Morbidity statistics relating to the civil population, other than fragmentary clinical records, are unobtainable.

Analysis of reports from ships and stations of the Navy during 1889 and 1890 show that from 20 to 75 per cent of the various complements were attacked. While most of the reports speak of the disease as mild, certain of them mention complicating pneumonia and nephritis, and the disease at the naval station, San Francisco, seems to have been associated with a case fatality rate of 4 per cent, all the deaths being caused by pneumonia.

It is significant that the annual death rate per thousand for disease in the Navy in 1889 was 10.7. In 1887 it was 7.6 and in 1888, 9.2. Since 1889 the rate has not reached that figure until the present pandemic.

The annual death rate per 100,000 for pneumonia is also very significant. This rate in 1887 was 62.38; 1888, 70.31; and in 1889,

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Chart No. 5

178.26; 1890, 169.95, and thereafter it did not again reach 100 until 1917, when it was 102.20.

Influenza in the Navy, 1889-90.

The following summary of the influenza during the years 1889-90 is taken from the annual report of the Surgeon General of the Navy for the year 1890:

Prepared by Passed Assistant Surgeon Frank Anderson, United States Navy.

In response to the circular issued by the Bureau of Medicine and Surgery, requesting information relative to the recent influenza pandemic, replies have been received from 41 medical officers stationed as follows:

European Squadron	4
Atlantic coast of North America	23
Gulf coast of North America	1
Vessels cruising in the West Indies	3
Atlantic coast of South America	1
Pacific coast of North America	7
Hawaiian Islands	1
China	1

These reports embrace a period extending from the first appearance of the disease in December, 1889, to April 10, 1890, and will be considered in the order indicated above.

The Chicago, Boston, and Atlanta arrived at Lisbon, Portugal, on December 21, 1889, the Yorktown on the 23rd.

Influenza had already been epidemic at this port for some weeks; more than 600 cases had been reported, and the number was daily increasing. The first case observed in the fleet occurred on the Chicago on December 23, two days after arrival, in an officer who had been on shore 36 hours previous to being attacked. Other cases followed each day in persons who had been on shore from 24 to 36 hours previous to being taken sick, and it was not until December 30 that a case occurred in a man who had not been out of the ship. The disease made its first appearance on the Boston and Yorktown on December 28, but did not break out upon the Atlanta until December 30, nine days after arrival. In regard to these last three vessels the reports do not state whether the first cases occurring on board were in persons who had been on shore, as was the case on the Chicago.

The following table shows the number of men on each ship, the dates of appearance of first and last cases, the time when the epidemic reached its maximum, the duration of the epidemic on board, and the percentage of persons attacked:

Name of vessel.	Complement	First case.	Height of epidemic.	Last case.	Duration of epidemic.	Per cent attacked.
					Days
Chicago	470	Dec. 23	Jan. 2	Jan. 21	29	60.0
Boston	315	Dec. 28	Jan. 2	Jan. 27	30	27.0
Atlanta	315	Dec. 30	Jan. 7	Jan. 24	25	27.0
Yorktown	190	Dec. 28	Jan. 3	Jan. 9	12	26.1

The crews of these vessels are composed chiefly of young and middle-aged men, and there is nothing to report as to a particular susceptibility manifested at any one period of life. All were subjected to much the same influences; and officers, sailors, marines, and engineers' force all suffered from the disease, with a somewhat smaller percentage of cases perhaps among the firemen and coal heavers.

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The following symptoms are recorded as prominent in the cases that occurred on these vessels: (a) Of the nervous system. Mental depression, melancholia, utter prostation, and wakefulness. Frontal headache, pain in the orbital regions, back, and limbs. Vertigo and tendency to syncope were experienced in some cases.

(b) Of the respiratory and circulatory organs. Fever preceded by chill. Temperature, 100.5°-104°. Catarrhal inflammation of respiratory passages in nearly every case. Difficulty in taking deep inspiration. Suffocative feeling. Little or no expectoration. Irregularity of heart beat in one case. Pulse ranging from 105 to 115 (in some cases it reached 120) slowly subsiding to normal and remaining weak for some days.

(c) Of the digestive organs. Loss of appetite, furred tongue, foul breath, nausea, occasionally vomiting during the chill. At times diarrhea. The derangement of digestion generally continued several days and was not readily amenable to treatment.

(d) Of the skin. Skin generally moist, often profuse perspiration. No eruptions were observed other than herpes labialis in two cases.

The following complications were observed: Pneumonia, pleuritis, and acute rheumatism. Empyema, phlebitis, persistent diarrhea occurred as sequelae in rare instances; but marked debility and bronchial catarrh commonly followed an attack.

Pneumonia occurred in five cases (one lobar) one of them proving fatal. There were 21 cases of relapse of the disease, as follows: Chicago, 13; Boston, 5; Atlanta, 3; Yorktown, 2.

Patients recovered quickly as a rule. The acute symptoms passed off rapidly, but patients were apt to remain debilitated for some time. Nine days was the longest time that a man remained on the sick list and one day the shortest, the average time upon the list being 2.8 days. There were of course many cases so mild that the patient did not go upon the list at all. The above figures refer to those who were sick enough to be excused from duty.

The disease did not have a marked influence upon other cases of sickness except in a case of emphysema and chronic bronchitis, in which a fatal termination was brought about.

Out f 486 cases of influenza occurring in the fleet there was but one death, a mortality of about one-fifth of 1 per cent. In this instance croupous pneumonia, involving the entire left lobe, was the cause of death.

Treatment.--Antipyrine and quinine were administered when a sedative action was desired. Salicylate of soda was given with marked benefit when rheumatism existed. Stimulants were administered only in complicated cases or where there was unusual debility.

It is the opinion of one medical officer only that the disease was positively contagious. One considers it probably so. Another believes it to be not contagious. The opinion of the fourth medical officer on this question is not expressed.

Locality.	First case.	Maximum.	Last case.	Duration of epidemic.
				Days.
Portsmouth, N.H.	Dec. 20	Jan. 15	Feb. 15	57
Boston	Dec. 21	Jan. 15	Feb. 27	68
Newport	Dec. 19	Jan. 15	Feb. 7	40
New York	Dec. 16	Jan. 1	Jan. 26	41
Philadelphia	Dec. 16	Jan. 5	Jan. 28	53
Annapolis	Dec. 25	Jan. 7	Jan. 21	27
Washington	Dec. 27	Jan. 13	Feb. 14	49
Richmond, Va.	Dec. 11	------	Feb. 12	32
Norfolk, Va.	Dec. 26	Jan. 15	Feb. 28	64

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These reports are from various medical officers stationed at the above places and on different duty, some referring to navy yards and receiving or training ships and some to hospitals. The earliest and latest cases reported are taken as showing the extreme range of the epidemic at each locality.

The estimates as to the percentage of population attacked necessarily vary widely and can only be approximate, as the observations in some cases apply to only a small number of persons in a ship or barracks and in others to the population in the neighborhood of the station.

In Portsmouth, N.H., 32 per cent of the persons connected with the naval station were attacked. This includes women and children.

In Boston 8 per cent of those living on the receiving ship and 25 per cent of those living on shore and connected with the station suffered from the disease.

At Newport 21 per cent of the boys upon the training ship and 20 per cent of the population of the town, including both sexes and all ages, were attacked.

In New York 8 per cent of the complement of the training ship and 20 per cent of the marine garrison and officers of the yard, including families, were taken sick.

In Philadelphia 33¹/3 per cent is about the average of the various estimates formed. This applies to all ages and sexes.

At Annapolis, out of 450 officers, cadets, and enlisted men, 56 per cent were attacked. The percentage of sickness among the cadets alone was 75.

At Washington 20 per cent of the marine garrison were attacked, but taking into consideration all persons living in or around or employed in the navy yard, it is estimated that 70 per cent suffered from influenza.

At Richmond, Va., the disease did not become epidemic upon the vessels stationed there, but a few mild cases occurred.

At Norfolk, Va., from 20 per cent to 25 per cent of all ages and sexes were attacked. On the receiving ship 75 per cent of the ship's company were taken sick.

The majority of these observations apply to men in early adult or middle life, and therefore do not justify conclusions as to a greater susceptibility at any particular period of life or on the part of one sex more than the other. But at the Naval Academy 75 per cent of the cadets were attacked, while at the home for aged sailors at Philadelphia only 2 cases are recorded among the 196 inmates, which tends to show that early life suffered more than old age.

In the above series of observations the following symptoms are recorded as prominent:

(a) Of the nervous system.--Chill followed by fever; the temperature rarely rising above 103°. Insomnia and mental depression, in one case stupor lasting three days. Cephalgia, neuralgia of the great nerve trunks, pain in bones and muscles. In exceptional cases, spinal hyperaesthesia on pressure, a peculiar sinking lassitude indicative of collapse centered in the great nervous plexuses surrounding heart and stomach.

(b) Of the respiratory and circulatory organs.--Nasal catarrh, with photophobia, epistaxis, bronchitis, diminished heart power, rapid respiration, and weak pulse.

(c) Of the digestive organs.--Furred tongue, anorexia, vomiting, constipation, usually in commencement of disease, sometimes sudden diarrhea and evidence of catarrhal disturbance of gastro-intestinal canal (so-called abdominal cases).

(d) Of the skin.--Hyperaesthesia. General flushing of the skin, followed in some cases by a papular or pustular eruption. Urticaria. Sometimes the skin was unusually dry; sometimes there was sweating. Glandular swellings about the neck in a few cases.

Among the complications of the disease as it appeared on this coast are recorded bronchitis, neuralgia, rheumatism, pneumonia, nephritis, and conjunctivitis. At the Naval Academy several cases of otitis media followed the disease. In one instance pericarditis and in one, severe facial neuralgia. In two cases albuminuria is reported as continuing after the influenza disappeared.

Not many cases of pneumonia are reported. From Boston two cases of catarrhal pneumonia are reported. In Newport pneumonia is reported to have occurred in 3 per cent of the cases. In New York three cases of lobar, in Philadelphia two cases of lobar, and in Annapolis two cases of lobar pneumonia occurred. In Washington there were three cases of catarrhal pneumonia and in Norfolk one case.

In New York relapse is reported in 4 per cent of the cases in Newport in less than 1 per cent. From Boston there are reported two cases of relapse;

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from Portsmouth 3, Philadelphia, 2, Washington 3, Norfolk 6. At Annapolis there were no relapses.

Convalescence was varied, as follows: Portsmouth, protracted; Boston, slow, with tendency to relapse on exposure to bad weather; Newport, rapid in men and children, slow in women; New York, rapid in the training ship, in other instances tardy, with listlessness, debility, and harassing cough; Philadelphia, acute symptoms passed off rapidly, but debility continued. When throat was involved it was slow. Annapolis, slow; patients long debilitated; Washington, all cases slow and tedious; Richmond, rapid; Norfolk, rapid in uncomplicated cases, slow in others.

The influence of the disease upon other diseases was, as a rule, unfavorable and tended to aggravate them. It increased the liability to attacks and dminished the power to resist. It was observed to render cases of gonorrhea peculiarly obstinate. Death is reported to have been accelerated in phthisis and in a case of hydronephrosis.

Only one death is reported from any of the naval stations along this coast. This occurred at Boston and is attributed to cerebral congestion.

Treatment.--Antipyrine and antifebrin were administered when there was not excessive depression and usually relieved pain. Salicylates were employed when rheumatism existed as a complication, and proved satisfactory. Quinine and whisky, were administered when there was much depression. One oifficer employed only rest in bed with occasional warm baths and little or no medication. This treatment was satisfactory and the cases seemed to do quite as well as where other more active measures were employed.

On this coast only two medical officers were led to regard the disease as contagious. One considers it infectious and the others are of the opinion that influenza is not a contagious disease.

But one report has been received from this region, viz, from the naval station at Pensacola, Fla., under date of March 5. The disease had not as yet been observed there.

Three vessels cruising in the West Indies report no cases having occurred on board. During the time when the disease was epidemic in the United States these vessels were visiting ports in Haiti, Jamaica, and Cuba. Some cases of influenza were said to have occurred in these islands, but, if they were genuine cases at all, they were few in number and mild in character.

The only report from this region is from the steamer Tallapoosa, stationed at Montevideo, in Uruguay. The disease appeared on this vessel on February 1; the epidemic reached its height on February 20; and disappeared March 10, having prevailed 38 days. The complement of this vessel numbers 161 all told, and of this number 20 per cent were attacked. The prominent symptoms were neuralgia of the scalp, pain in the back, lumbar region, and along the sciatic nerve. There was marked anorexia. There were no eruptions, but sweating was a well-marked feature of the disease. Obstinate bronchitis was the only complication. There were no cases of pneumonia and no deaths. Quinine and antipyrine were the remedies used. It is the opinion of this medical officer that the disease is not contagious.

Reports from this coast were recieved as follows: Sitka, Alaska, 1; Mare Island, 4; San Francisco, 1; Oakland, 1.

Alaska.--In Alaska the disease did not appear in an epidemic form and no characteristic cases are reported. Nasal, pharyngeal, and bronchial catarrh are said to have been more frequent than usual.

San Francisco, Oakland, Mare Island.--Taking these reports collectively the first case occurred on January 1. From that time the disease spread and the epidemic attained its maximum of intensity about January 20. It then gradually

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declined, and by February 10 had subsided, having continued about 40 days.

Out of a force of about 1,000 men at the Marie Island naval station, 15 per cent suffered from the disease. Four cases of relapse were reported.

The most prominent symptoms were--

(a) Of the Nervous System.--Pain in lumbar region. Intercostal neuralgia. Supraorbital neuralgia with coryza, often confined to one side; cephalgia.

(b) Of the respiratory and circulator system.--Bronchitis with fever. Temperature first day, 102.5° to 103.5°, dropping to 101° on second day and normal on the third.

(c) Of the digestive organs.--Anorexia, coated tongue, constipation.

(d) Of the skin.--Relaxed skin; perspiration at intervals of several hours coincident with slight reduction of temperature. In some cases profuse perspiration upon departure of fever.

No special complications were observed, but there was extreme muscular debility out of proportion to the gravity of the disease and lasting for weeks.

In 150 cases of influenza, 11 cases of pneumonia occurred, all croupous.

The mortality was 4 per cent, all the deaths being caused by pneumonia.

Treatment.--Aperients, mineral acids, antipyrine, and quinine were the remedies employed and gave satisfactory results.

It is the opinion of the medical officers on the Pacific coast that the disease is not contagious.

A vessel lying at Oakland did not have any cases of influenza on board, though the disease was quite prevalent in the town.

A report from Honolulu states that the disease was still epidemic there as late as April 10, but the time when it first appeared is not stated.

At Canton, China, under same date (Apr. 10) the disease is reported not to have been observed.

In 1917 the death rate for influenza was lower again--17.2 per 100,000. The rate for influenza, however, does not mean so much in years when the disease is not generally recogtnized, and it is significant that the death rate for all forms of pneumonia in the registration area in 1917 was 149.3 per 100,000, as compared with 137.3 in 1916, the highest rate since 1900. In 1900 the rate was 180.5, probably an influenza year, although the rate for influenza itself was higher in 1901 when it was 32.2.

The report of the registrar general of England and Wales for the year 1916 shows that the numbers of deaths from influenza reported by years from 1911 were as follows;

Thus the number of deaths reported in 1915 was nearly double that for preceding years.

Influenza was epidemic in various parts of Europe throughout 1918, and undoubtedly the earlier outbreaks were carried over from 1917. The files of The Lancet indicate that a more or less widespread

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epidemic occurred in England in the spring of 1915. The disease does not appear to have been as prevalent in 1916 as in 1915, but in 1917, among the military forces, cases of so-called "purulent bronchitis" occurred which were fundamentally the same as the rapidly fatal cases of influenzal pneumonia so frequently seen at the height of the pandemic.

An epidemic of purulent bronchitis was reported from a British Army base in northern France in January, 1917, whilst an epidemic of influenza was in progress. This outbreak began in December, 1916. Later, in the spring of 1917, similar cases of purulent bronchitis were treated at Aldershot, England. These cases are noteworthy because they seem to have been similar in all respects to the fatal types of influenzal pneumonia so commonly seen in all parts of the world during the autumn of 1918. The epidemic referred to was reported by Hammond, Rolland, and Shore in The Lancet, July 14, 1917. They remark that although the earlier cases were admitted during December, 1916, it was not until the end of the following January, when exceptional cold prevailed, that the disease assumed epidemic proportions. The disease was very fatal and was the cause of death in 45.5 per cent of 156 consecutive cases coming to necropsy. Clinically, the prominent signs were the characteristic yellow purulent or mucopurulent sputum, tachycardia, and cyanosis. The pathological findings were thick purulent material in the smaller bronchi from which frequently air was excluded; in some cases secondary broncho-pneumonia, edema, and emphysema. The lungs were almost always bulky. The cause of the disease was thought to be the Pfeiffer bacillus because of its almost constant occurrence in the sputum and in the pus in the bronchioles. In some typical cases it occurred apart from the presence of any other microorganism, although more frequently pneumococci or streptococci were associated with it.

Abrahams, Hallows, Eyre, and French in The Lancet, September 8, 1917, reported their observations of scores of similar cases in the Aldershot command. Their conclusions were almost identical with those recorded above. Case fatality rates were approximately 50 per cent. Stress was laid upon a peculiar dusky heliotrope type of cyanosis of the face, lips, and ears, as a characteristic sign. They found that whether cultures were made from the sputum itself or from material obtained by lung puncture, or from the blood or organs post mortem, influenza bacilli and pneumococci were constantly found and they conjectured that the disease started as an influenza bacillus infection, terminating in fatal cases as a pneumonococcus septicemia, the pneumococcus increasing its virulence by growth in symbiosis with B. Influenzae.

Because it was taken for granted that B. Influenzae was without lethal effect upon the lower animals no virulence estimations were attempted. However, two small rabbits were subjected to intrapulmonary inoculations with strains of B. Influenzae isolated from two mild cases of purulent bronchitis. The first rabbit died 12 hours later because of accidental puncture of a large vessel. The second experiment was successful, the rabbit dying on the fifth day with pleural effusion and lesions in the lungs. The polymorphonuclear leucocytes in the pleural fluid were packed with influenza bacilli and pure cultures of the micro-organisms were recovered from the lung tissues, heart, blood, and spleen.

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Later, in The Lancet, January 4, 1919, Abrahams, Hallows, and French reported in detail, "A further investigation into influenzo-pneumococcal and influenzo-streptococcal septicaemia" as seen during the epidemics of influenza in September and October, 1918. They concluded, after ample opportunities for broadening and extending their views, that the "purulent bronchitis' type is merely one of many and that the cases seen in 1916 and 1917 represent fundamentally the same condition as the fatal "influenzal pneumonia" seen at the height of the pandemic, in which, they believed, "influenzo-pneumococcal septicaemia" was responsible for most, if not all, fatal cases, it being only a matter of degree whether there occurred "purulent bronchitis," "capillary bronchitis" or "broncho-pneumonia."

Roughly speaking, among the cases of influenza seen at Aldershot, 80 per cent took an ordinary uncomplicated course and 20 per cent showed pulmonary complications in some degree. Eight per cent were moderately severe and 12 per cent of the patients were desperately ill. For the latter group the case-fatality rate was somewhere between 60 and 80 per cent. As compared with cases seen during the previous year they weres truck by the relative paucity and even absence of sputum, although in numerous instances typical cases of "purulent bronchitis" were also seen.

February, 1918.--Outbreaks were noted as follows:

		Cases.
U.S.S. Dubuque at the navy yard, New York		11
U.S.S. Madawaski, Cruiser and transport Force		37
U.S.S. New Jersey, Atlantic coast		220
U.S.S. Salem at the navy yard, Boston		30
United States Naval Radio School, Cambridge, Mass.		350-400

Eleven cases of pneumococcus-streptococcus pneumonia were associated with the outbreak at the Harvard Radio School in Cambridge. In the same month several cases of influenza complicated with streptococcus pneumonia occurred at the navy yard, Portsmouth, N.H., among the crew of the U.S.S. South Dakota and cases of epidemic influenza without complications occurred among the crew of the U.S.S. Leonidas at the same yard.

March, 1918--

		Cases.
U.S.S. Frederick at the navy yard, Portsmouth, N.H.		147
U.S.S. St. Louis at Norfolk, Va.		73
U.S.S. Charleston at Hampton Roads, Va.		55
U.S.S. Buffalo at Philadelphia, Pa.		21

The prevalence of influenza in epidemic form was also reported from the U.S.S. Georgia and the U.S.S. Kansas, Chesapeake Bay.

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April, 1918.--

U.S.S. North Carolina at Norfolk, Va.; 100 cases of a mild type.

U.S.S. Pensacola at the navy yard, Charleston, S.C.; mild epidemic; cases of short duration.

U.S.S. May, base 20, Rochefort, France, 25 per cent of the crew suddenly attacked.

U.S.S. Oregon at Mare Island, Cal., approximately 450 men, two-thirds of the ship's company attacked by influenza.

U.S.S. Bath, Hampton Roads, Va.; 38 cases with 1 death.

United States Naval Training Camp, Gulfport, Miss.; mild epidemic but higher percentage of complement attacked than during the subsequent fall epidemic.

Seventh Regiment, United States Marine Corps, Santiago de Cuba; mild epidemic which spread rapidly. Men who were attacked at this time apparently possessed immunity later, during the fall and winter.

United States Submarine Base, San Pedro, Cal.; an epidemic of 10 days' duration following the visit of a Japanese ship on board which the disease was prevalent.

United States Naval Training Camp, San Diego, Cal.; following the visit of a Japanese Squadron an epidemic occurred on the station; 9 per cent of the complement were attacked, 410 cases. Pneumonia complicated in 12 cases.

May, 1918.--

		Cases.
U.S.S. Dixie, Queenstown, Ireland (11 per cent of the crew attacked)		77
U.S.S. Texas, with British Grand fleet 92 deaths)		80
U.S.S. Birmingham at Gibraltar 910-day epidemic)		78
U.S.S. Chester at Plymouth, England (20 per cent of the crew affected)		80
U.S.S. Nashville, Passage, Gibraltar to Bizerti, Africa (47 per cent of the crew attacked)		91
United States Naval Air Station, Dunkirk, France (90 per cent of the complement attacked)
United States Naval Air Station, Gujan-Mestras, France (40 per cent of the complement attacked)		72

Severe epidemics occurred in China in the Yangtze Valley, in the vicinity of Shanghai and in Peking, in May, June, and August. In September, October, and November epidemics prevailed throughout China causing high mortality rates.

June, 1918.--

		Cases.
U.S.S. Machias at Gibraltar (25 per cent of the crews attacked)		63
U.S.S. Brooklyn at Vladivostok, Siberia (successive epidemics for 8 weeks)
U.S.S. Monterey, Pearl Harbor, Hawaii (66 per cent of the crew attacked)		124
U.S.S. Castine at Gibraltar (18 per cent of the crew attacked)		32
U.S.S. New York with British Grand Fleet (10 percent of the crew attacked, serious pulmonary complications in 8 per cent of the cases, 2 deaths)		138

		Cases.
U.S.S. Tallahassee at Key West, Fla. (20 per cent of the crew attacked)		76
U.S.S. Dubuque at navy yard, New York (5 per cent of the crew attacked)
U.S.S. Plattsburg, Atlantic Transport Service (sporadic cases occurred throughout the month.)
U.S.S. Galatea, Azores (50 per cent of the crew attacked)		30
U.S.S. Venetia at Gibraltar (19 per cent of the crew attacked)		16
United States Naval Air Station, Wexford, Ireland, epidemic of 2 weeks' duration		65
United States Naval Air Station, L'Abervrach Finisterre, France		69
United States Naval Air Station, Fromentine, Vendée, France (mild epidemic of 2 weeks' duration)		32
United States Naval Air Station, Queenstown, Ireland (epidemic began July; cases occurred to November 1)		243
United States Naval Air Station, Guipavas, France		26
United States Naval Air Station, La Trinité France (28 per cent of the complement attacked, 2 cases of complicating pneumonia)		40

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August, 1918.--

		Cases.
United States Naval Air Station, St. Trojan, France (63 per cent of the complement affected at one time, 20 cases of complicating pneumonia, 1 of meningitis; 5 deaths)		215
United States Naval Station, Cristobal, Canal Zone (epidemic of the pandemic type appeared will before progressive spread began in the United States)

At the navy yard, Mare Island, Cal., the admission rate per 1,000 for influenza for the year 1918 was 259.8, as compared with 6.9 for 1915, 1.9 for 1916, and 35.9 for 1917. Excluding the fall epidemic, the admission rate for 19187 would have been 62.9 per 1,000, which indicates that influenza was undoubtedly on the increase long before the storm broke in October.

The monthly curve for influenza at that station during the year 1918 shows a higher mark in January than in December, 1917. The curve rose sharply to an apex in March, 1918, and then fell abruptly, so that in May it as much lower than in January. It then rose slowly through June, July, and August, reaching the level of January in the latter month. An unaccountable drop occurred in September to the lowest point reached during the year. This was followed by a tremendous rise in October; then a drop to nearly one-half in November and a still further drop in December, when the curve again reached the level of January.

In the sanitary report from United States Navy Yard, Mare Island, Cal., for the month of July, 1918, it was noted that "practically all cases of pneumonia developed among detentioners, * * * and among those quartered in the barracks (naval training camp barrack building)." "All had been treated for influenza or 'colds' and most of the cases were sent to hospital with a diagnosis of influenza or bronchitis and the diagnosis was changed at the hospital to pneumonia as the result of later developments." "Most of the pneumonia cases were atypical, suggesting the bronchial type, and there was no case of frank lobar pneumonia."

During the month of March, 1918, 1,066 employees of the Ford Motor Co., detroit, Mich., were sent home from the factory with influenza. The number of cases gradually increased from 10 on March 1 to 54 on March 27, and 145 on March 28. From March 289 to April 8, an average of 168 cases occurred. April 9 a sudden drop to 65 took place and thereafter the incidence continued to lessen until May 8, when the number of cases dropped to 10, which seemed to be the average number of cases occurring normally at that time. It was estimated that the number of patients sent home from work represented about half the total number of cases occurring among employees. During this spring epidemic the average time lost per patient was 3.57 days.

Several cargo vessels from Europe arrived in Philadelphia early in the summer with influenza cases on board. From the British steamship City of Exeter, arriving at Philadelphia June 22 from Liverpool, 27 lascars and an English quartermaster were removed to hospital desperately ill with pneumonia. Two steamships from Norway and another from some Scandinavian port arrived in New York August 14 and 15 with a number of patients ill with influenza. The Norwegian liner Bergensford,, arriving at New York August 12, reported a large number of cases resembling influenza during passage. At about the same time a steamship arrived at Newport News with almost the entire crew affected. A liner, arriving at New York August 18, reported the development of 21 cases of influenza among passengers and crew during the voyage. During the month of August a sharp outbreak occurred at Fort Morgan, Ala.

--2425--

By the middle of July it was evident from weekly statistics of the Navy and reports from ships and stations, as well as reports from Spain, Austria, Germany, Switzerland, France, Great Britain, Hawaii, and elsewhere, that influenza was again pandemic, but at that time it could not be foretold that epidemics were shortly to occur associated with a type of pneumonia scarcely equalled in intensity of infection by anything except the pneumonic form of plague and causing case-fatality rates for influenza exceeding 4 per cent in many localities.

Late in August the type of cases changed; the disease began to spread progressively from one community to another. The percentage of pulmonary complications increased beyond comparison with regard to the earlier epidemics, and influenzal pneumonia frequently began very early in the disease.

The effect of influenza on the crude death rate of the Navy is strikingly shown on chart No. 1 on page 355 and chart No. 2 on page 356.

In the United States the first cases of this phase of the pandemic were recognized in the receiving ship at Boston, Mass. (Commonwealth Pier). Scattered cases of the same type had appeared among the civilian population of Boston earlier, but the serious nature of the disease was not recognized until after the beginning of the great epidemic.

It is possible that the causative agent of influenza was introduced afresh from European ports among the personnel of the receiving ship, but no particular vessel was recognized as being responsible for the introduction leading to the outbreak in question.

Epidemics of like character occurred almost simultaneously in most parts of the world. In the Canal Zone a rapidly spreading epidemic occurred even before progressive spread began in the United States. The epidemic in China began in the latter part of August. By September 1, serious epidemics were in progress in South Africa, India, and Japan, as well as in many parts of Europe. Influenza of malignant type was apparently introduced into Rio de Janeiro, Brazil, from Spain, September 17, by the ship Demerara, sailing from Lisbon, Portugal, via Dakar, Africa. The epidemic in Spain had got well ahead in May. In Switzerland the epidemic began suddenly about July 1, and during July 53,698 cases of influenza were reported, as compared with 34 cases for the previous six months. In succeeding months cases were reported as follows: August, 41,626; September, 41,642; October 263,399; November, 159,422; and December, 104,612.

A comparatively mild epidemic of influenza and pneumonia prevailed in France from April 1 to August 1. About August 22 a violent outbreak began among the French forces in the vicinity of Brest. The comparatively mild earlier epidemic had apparently subsided about August 1, and the French authorities decided to continue the enrollment of the class of 1920. In the latter part of the month the violent epidemic mentioned began and reached its height in September, the pneumonia continuing into October.

It might be concluded that the cases of purulent bronchitis which occurred in northern France and England in 1917 were forerunners of the severe types of influenza which were so numerous during the

--2426--

Chart 6:U.S. Navy.
Influenza Epidemics--1918.
Case Incidence per 1000 of Complement by Days
at Seventeen of the Larger Shore Stations in the United States

fall of 1918. Influenza probably continued in epidemic form in France during 1917 and the spring of 1918, when it spread to Spain. In Spain the disease spread more rapidly and more extensively, and about July 1 was introduced into Switzerland either from this source or directly from France. The more serious epidemic in France, which began in August, 1918, may have been due to return spread from Spain or Switzerland or both. At any rate, it is reasonable to suppose that late in August influenza of severe type was spread from French, Spanish, and Portuguese seaports to the Orient, South Africa, the United States, and South America.

The epidemic at Commonwealth Pier, the receiving ship at Boston, may be said to have begun August 27, 1918, when three cases of influenza were admitted to the sick list, although naturally they were not recognized on that day as the beginning of rapidly spreading outbreaks in the Navy with increasing case-fatality rates. The following day 8 cases occurred, and on August 29, 58 cases, of which 50 were transferred to the United States Naval Hospital Chelsea, Mass., where cases among the medical staff began to occur in less than 48 hours.

The early cases occurring during the outbreaks at naval stations in the first naval district in the vicinity of Boston were characterized by very sudden onset, patients, frequently passing within a hour or two from an apparent healthy condition into a state of prostration.

At Commonwealth Pier the peak of the epidemic was reached on the sixth day and the major phase was over on the eighth day. Outbreaks followed promptly in practically all naval stations in the vicinity of Boston. No grouping or localization of cases could be detected at any station, nor could any relationship be traced between attacks at one station or ship and another. Between the naval radio school, Harvard University, where an extensive epidemic occurred, and Commonwealth Pier, where the first cases appeared, there was little contact. There was close relationship between Commonwealth pier and the Boston section base, as well as the naval aviation detachment in Cambridge, in both of which stations comparatively few cases occurred, while epidemics were in progress at other stations near by.

At the training camp on Bumkin Island, well out in the harbor, a short but severe epidemic began September 7, reaching its highest peak two days later and a second high peak September 12, after a decrease in the number of new cases September 11. The outbreak declined suddenly September 13, and was practically over by September 16.

The disease appeared in the navy yard, Portsmouth, N.H., in the course of a few days, where the greatest incidence was in the naval prison.

At the United States Naval Training Station, Newport, R.I., the epidemic began September 10, reached its peak seven days later, and terminated on the sixteenth day. The earliest cases among naval personnel in Newport occurred at the training station.

September 11, 22 cases appeared at the submarine base and 50 at the naval district base, New London, Conn.

--2427--

At this time, with the exception of the receiving ship, naval stations in the vicinity of New York City escaped epidemics for the most part, the outbreak at the United States Naval Training Camp, Pelham Bay Park, not beginning until September 24.

Influenza was probably introduced into the navy yard, Philadelphia, Pa., September 6, by a draft of men from Boston, 6 cases developing September 11 among the receiving ship personnel. A draft of several hundred men left the navy yard, Philadelphia, for Quebec on September 10 and six cases of influenza developed among them upon arrival at Quebec, September 11.

The outbreak in the receiving ship at Philadelphia was severe. The greatest number of cases occurred on the fifth day, but the epidemic did not begin to subside until the tenth day.

On September 11, epidemics also began at the marine barracks, Quantico, Va.; navy yard, Charleston, S.C.; and at the United States Naval Station, Pensacola, Fla. The epidemic began at G reat Lakes S eptember 12; September 13, at the naval training station, Hampton Roads, Va.; September 16, at the receiving ship and naval station, Norfolk, Va.; also at Wissahickon Barracks, Cape May, N.J.

September 17, the disease was introduced into the navy yard, Puget Sound, Wash., by a draft of 334 men from the navy yard, Philadelphia, Pa., 11 of whom were ill with influenza upon arrival. The disease became epidemic in the city of Seattle and at the naval training camp in Seattle about September 25.

A severe epidemic began at the naval station, New Orleans, La., September 26. At the naval training camp, Gulfport, Miss., an outbreak occurred September 28, and this also proved to be relatively severe.

As mentioned above, a mild but somewhat extensive epidemic of influenza occurred at the naval training camp, San diego, Cal., in the spring of 1918. The disease was prevalent all through the month of September, the number of cases from September 1 ranging from 2 or 3 to 10 on September 9. From that day there was a g radual increase to 35 cases on September 18, after which the number of new cases per day decreased slightly until September 24 when 33 cases occurred, increasing to 80 new cases September 25, which marked the peak of a relatively mild epidemic. Apparently the course of the epidemic at this station was modified by the presence of men who had passed through the spring epidemic.

Influenza was introduced into the navy yard, Mare Island, Cal., September 25, by a man who became ill on the train returning from leave in Oklahoma. The health officer of San Francisco reported to the naval authorities that six cases had occurred in the city during the week ending September 21.

To recapitulate, epidemics began at naval stations in the United States as follows:

Receiving ship, Boston	Aug. 28.
Harvard Radio School, Cambridge, Mass.	Sept. 4.
Bumkin Island, Boston, Mass.	Sept. 7.
Navy yard, Portsmouth, N.H.	Sept. 7.
Naval training station, Newport, R.I.	Sept. 10.
Submarine base and naval district base, New London, Conn.	Sept. 11.
Navy yard, Philadelphia, Pa.	Sept. 11.
Marine barracks, Quantico, Va.	Sept. 11.
Navy yard, Charleston, S.C.	Sept. 11

--2428--

Chart No. 7

Logarithmic scale of ordinates (rates); arithmetic scale for abscissae (weeks). Certain shore stations of the Navy in the United States. Annual death rates by weeks, September 1 to December 31, 1918, influenza, including influenzal pneumonia.

Naval station, Pensacola, Fla.	Sept. 11.
Naval training station, Great Lakes, Ill.	Sept. 11.
Naval training station, Hampton Roads, Va.	Sept. 13.
Receiving ship, New York	Sept. 15.
Receiving ship, Norfolk (St. Helena Station)	Sept. 16.
Wissahickon barracks, Cape May, N.J.	Sept. 16.
Navy yard, Puget Sound, Wash.	Sept. 17.
Naval training camp, Pelham Bay Park, N.Y.	Sept. 24.
Naval training camp, Seattle, Wash.	Sept. 25.
Navy yard, Mare Island, Cal.	Sept. 25.
Naval station, New Orleans, La.	Sept. 26.
Naval training camp, Gulfport, Miss.	Sept. 28.

The general characteristics of the outbreaks at shore stations in the United States in respect to time of onset, duration and comparative incidence are shown in chart No. 6, indicating the incidence per thousand of complement by days, the curves covering the major epidemic at each station within the period, August 27 to December 31, 1918.

Charts Nos. 7 and 8 show annual death rates by weeks, epidemic period, September 1 to December 31, 1918, influenza (including influenzal pneumonia) for each of the 17 stations for which the influenza case-incidence rate by days is shown in chart No. 6.

Each station is represented by a color, and the same color is used for that station in both the morbidity curve and the mortality curve.

Charts Nos. 9 and 10 show annual death rates (all causes) by weeks during the epidemic period, for certain cities of the United States. The data were obtained from the weekly index published by the United States Bureau of the Census. Comparisons may be made because the excess mortality in these cities during the epidemic period was due almost, if not entirely, to influenza.

A striking feature of most of the epidemics at naval stations was the rapidity of onset and the rapidity with which the peak of the epidemic was reached. The character of the onset was frequently very similar to outbreaks of scarlet fever and other diseases, in instances traced to a common source of infection. The peak of the epidemic was usually reached in from 6 to 10 days.

Table No. 1 shows the accumulated percentages of complements attacked day by day from the first day of the epidemic at each of 17 of the larger shore stations of the Navy in the United States.

Table No. 2 shows cumulative case fatality rates per 100 of complement, influenza, including influenzal pneumonia, by five-day periods fro 15 stations.

Table No. 3 shows the epidemic influenza attack rate per 1,000, the epidemic death rate per 1,000, and the case-fatality rate per 100, all cases of influenza, including influenzal pneumonia, for the period of the primary epidemic at each of these stations.

Annual death rates, by weeks, during the epidemic are shown for these stations in Table No. 4.

Table No. 5 shows annual death rates per 1,000 by weeks, for pneumonia, all forms, exclusive of influenzal pneumonia, for the same stations.

Table No. 6 shows the death rate per 1,000 during the 25 weeks, September 7 to March 1, inclusive, epidemic period in the United States, for 42 cities, from influenza and pneumonia (all forms) United States Bureau of the Census figures.

--2429--

--2430--

Chart No. 8

Logarithmic scale. Certain shore stations of the Navy in the United States. Annual death rates by weeks, September 1, to December 31, 1918, influenza, including influenzal pneumonia.

--2431--

Week.	Training camp, Pelham Bay Park, N.Y.		Training station, Great Lakes, Ill.		Training camp, San Diego, Cal.		Training camp, Charleston, S.C.		Training station, Hampton Roads, Va.		Training station, Norfolk, Va.
	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.
Sept. 7	------	------	------	------	------	------	------	------	------	------	------	------
Sept. 14	------	------	1	1.09	------	------	------	------	------	------	------	------
Sept. 21	1	3.43	97	112.32	1	10.92	1	13.00	------	------	------	------
Sept. 28	------	------	489	566.28	------	------	5	66.56	19	86.84	8	51.48
Oct. 5	13	46.28	197	230.88	1	10.40	2	24.96	66	312.00	37	243.88
Oct. 12	64	232.44	58	69.16	------	------	2	23.92	47	227.24	18	119.60
Oct. 19	31	117.52	18	21.32	2	20.80	4	48.88	23	107.64	2	13.52
Oct. 26	10	37.96	15	18.20	------	------	3	35.88	3	13.52	1	6.76
Nov. 2	3	12.48	9	11.44	1	10.40	1	11.44	4	19.24	1	6.76
Nov. 9	2	8.84	5	6.76	2	20.80	3	36.40	4	19.76	1	6.24
Nov. 16	1	4.73	9	13.00	5	56.68	3	36.40	1	4.88	------	------
Nov. 23	------	------	6	8.84	1	12.48	1	11.96	------	------	------	------
Nov. 30	------	------	2	3.22	2	24.96	------	------	------	------	------	------
Dec. 7	------	------	3	4.94	2	26.00	------	------	1	3.79	------	------
Dec. 14	2	6.76	5	7.80	2	26.52	1	16.12	5	18.72	------	------
Dec. 21	4	11.44	4	6.24	------	------	------	------	2	7.28	1	7.28
Dec. 28	10	32.76	3	4.78	------	------	------	------	------	------	------	------
Dec. 29-31	4	32.94	3	11.59	------	------	------	------	------	------	------	------
Total	145	31.56	924	72.12	19	12.69	26	20.25	175	44.94	69	27.15
Week.	Training camp, Puget Sound Wash.		Training camp, Cape May, N.J.		Receiving ship, Philadelphia		Training camp, Bumkin Island, Mass.		Training camp, Gulfport, Miss.		Training camp, Seattle, Wash.
	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.
Sept. 7	------	------	------	------	------	------	------	------	------	------	------	------
Sept. 14	------	------	------	------	1	7.80	1	52.00	------	------	------	------
Sept. 21	------	------	------	------	14	113.36	6	338.00	------	------	------	------
Sept. 28	7	55.64	6	174.20	29	237.12	1	57.20	1	29.64	2	24.44
Oct. 5	24	195.52	7	220.48	12	95.68	1	27.04	------	------	3	37.44
Oct. 12	20	157.04	1	33.80	13	107.64	------	------	2	63.96	20	253.24
Oct. 19	5	40.56	------	------	5	43.16	------	------	13	392.08	3	37.96
Oct. 26	1	7.80	------	------	------	------	------	------	2	50.96	2	25.48
Nov. 2	1	8.32	------	------	------	------	1	52.52	------	------	3	38.48
Nov. 9	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 16	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 23	2	18.20	------	------	1	7.28	------	------	------	------	------	------
Nov. 30	------	------	------	------	1	7.28	------	------	------	------	------	------
Dec. 7	------	------	------	------	------	------	------	------	------	------	------	------
Dec. 14	------	------	------	------	------	------	1	62.40	------	------	1	11.44
Dec. 21	------	------	------	------	------	------	------	------	------	------	------	------
Dec. 28	------	------	------	------	2	21.84	------	------	------	------	------	------
Dec. 29-31	------	------	------	------	------	------	------	------	------	------	------	------
Total	60	30.90	14	24.30	78	37.26	11	30.27	18	32.46	34	24.45

--2432--

Chart No. 9--Logarithimic scale. Certain cities in the United States. Annual death rates for all causes, by weeks during the epidemic period.

Week.	Receiving ship, Boston, Mass.		Training station, Newport, R.I.		Marine barracks, Quantico, Va.		Training station, New Orleans, La.		Naval station, Pensacola, Fla.		Total
	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.
Sept. 7	8	86.32	------	------	------	------	------	------	------	------	8	2.96
Sept. 14	19	217.36	2	9.88	------	------	------	------	------	------	24	8.32
Sept. 21	14	158.60	27	151.84	1	5.72	------	------	------	------	162	59.28
Sept. 28	5	67.08	55	315.12	25	141.96	------	------	1	9.36	653	243.36
Oct. 5	4	54.60	23	132.08	22	148.20	1	17.68	9	86.84	422	159.12
Oct. 12	------	------	5	30.16	20	131.04	11	223.08	10	91.00	291	111.80
Oct. 19	------	------	------	------	9	69.68	12	248.04	3	27.56	130	50.96
Oct. 26	------	------	------	------	------	------	6	123.76	------	------	43	16.64
Nov. 2	------	------	------	------	------	------	2	47.32	------	------	26	10.40
Nov. 9	------	------	------	------	13	75.92	------	------	------	------	30	11.96
Nov. 16	------	------	------	------	9	58.76	------	------	------	------	28	11.44
Nov. 23	------	------	------	------	16	139.96	------	------	------	------	25	9.36
Nov. 30	1	8.84	------	------	1	5.20	------	------	------	------	9	3.79
Dec. 7	1	7.80	------	------	1	5.20	------	------	------	------	8	3.27
Dec. 14	------	------	------	------	------	------	1	28.08	------	------	18	7.28
Dec. 21	------	------	------	1	8.32	------	------	------	------	------	12	4.99
Dec. 28	------	------	------	------	------	------	------	------	1	9.36	16	6.76
Dec. 29-31	------	------	------	------	------	------	------	------	------	------	7	7.68
Total	52	34.74	113	45.72	117	40.77	33	45.06	24	13.29	1,912	44.40

Week.	Training camp, Pelham Bay Park, N.Y.		Training station, Great Lakes, Ill.		Training camp, San Diego, Cal.		Training camp, Charleston, S.C.		Training station, Hampton Roads, Va.		Training station, Norfolk, Va.
	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.
Sept. 7	------	------	------	------	------	------	------	------	------	------	------	------
Sept. 14	------	------	2	2.36	------	------	------	------	1	4.73	1	6.24
Sept. 21	------	------	3	3.43	------	------	------	------	------	------	------	------
Sept. 28	------	------	14	16.12	------	------	2	26.52	------	------	------	------
Oct. 5	------	------	4	4.68	------	------	1	12.48	1	4.68	------	------
Oct. 12	3	10.40	1	1.96	------	------	------	------	------	------	------	------
Oct. 19	4	15.08	2	2.39	------	------	------	------	1	4.68	------	------
Oct. 26	------	------	2	2.44	------	------	------	------	------	------	1	6.76
Nov. 2	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 9	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 16	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 23	------	------	1	1.50	------	------	------	------	------	------	------	------
Nov. 30	1	4.42	------	------	------	------	------	------	------	------	------	------
Dec. 7	------	------	2	3.27	------	------	------	------	------	------	------	------
Dec. 14	------	------	1	1.61	------	------	------	------	------	------	------	------
Dec. 21	------	------	------	------	------	------	------	------	------	------	------	------
Dec. 28	------	------	------	------	------	------	------	------	------	------	------	------
Dec. 29-31	------	------	------	------	------	------	------	------	------	------	------	------
Total	8	1.74	32	2.49	------	------	3	2.31	3	.75	2	.68

--2433--

Week.	Training camp, Puget Sound Wash.		Training camp, Cape May, N.J.		Receiving ship, Philadelphia		Training camp, Bumkin Island, Mass.		Training camp, Gulfport, Miss.		Training camp, Seattle, Wash.
	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.
Sept. 7	------	------	------	------	------	------	------	------	------	------	------	------
Sept. 14	------	------	------	------	1	8.84	------	------	------	------	------	------
Sept. 21	------	------	------	------	------	------	------	------	------	------	------	------
Sept. 28	1	7.80	------	------	------	------	------	------	------	------	------	------
Oct. 5	------	------	------	------	------	------	------	------	------	------	------	------
Oct. 12	------	------	------	------	------	------	------	------	4	127.92	2	24.96
Oct. 19	------	------	------	------	------	------	------	------	------	------	1	12.48
Oct. 26	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 2	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 9	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 16	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 23	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 30	------	------	------	------	------	------	------	------	------	------	------	------
Dec. 7	------	------	------	------	------	------	------	------	------	------	------	------
Dec. 14	------	------	------	------	------	------	------	------	------	------	------	------
Dec. 21	------	------	------	------	------	------	------	------	------	------	------	------
Dec. 28	------	------	------	------	------	------	------	------	------	------	------	------
Dec. 29-31	------	------	------	------	------	------	------	------	------	------	------	------
Total	1	.51	------	------	1	.45	------	------	4	7.20	3	2.13
Week.	Receiving ship, Boston, Mass.		Training station, Newport, R.I.		Marine barracks, Quantico, Va.		Training station, New Orleans, La.		Naval station, Pensacola, Fla.		Total
	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.	Deaths.	Rate.
Sept. 7	------	------	------	------	------	------	------	------	------	------	------	------
Sept. 14	2	22.88	------	------	------	------	------	------	------	------	7	2.54
Sept. 21	1	10.92	2	10.92	------	------	------	------	------	------	6	2.23
Sept. 28	------	------	------	------	1	6.24	------	------	------	------	23	8.32
Oct. 5	------	------	------	------	1	6.24	------	------	------	------	7	2.60
Oct. 12	------	------	------	------	------	------	------	------	------	------	10	3.84
Oct. 19	------	------	------	------	1	7.28	------	------	------	------	9	3.53
Oct. 26	------	------	------	------	1	7.80	------	------	------	------	4	1.76
Nov. 2	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 9	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 16	------	------	------	------	------	------	------	------	------	------	------	------
Nov. 23	------	------	------	------	------	------	------	------	------	------	1	.39
Nov. 30	------	------	------	------	------	------	------	------	------	------	1	1.42
Dec. 7	------	------	------	------	------	------	------	------	------	------	2	.78
Dec. 14	------	------	------	------	------	------	------	------	------	------	1	.42
Dec. 21	------	------	------	------	------	------	------	------	------	------	------	------
Dec. 28	------	------	------	------	------	------	------	------	------	------	------	------
Dec. 29-31	------	------	------	------	------	------	------	------	------	------	------	------
Total	3	1.83	4	1.59	7	2.43	------	------	------	------	71	1.62

--2434--

Chart No. 10--Logarithmic scale. Certain cities in the United States. Annual death rates for all causes by weeks during the epidemic period.

City.	Deaths from--		Deaths from influenza and pneumonia (all forms).
	Influenza	Pneumonia (all forms)	Number.	Number per 1,000 population.
Total	84,355	56,659	141,014
Albany	570	178	748	6.6
Atlanta	59	795	854	4.2
Baltimore	1,956	3,006	4,962	7.4
Birmingham	902	278	1,180	6.0
Boston	4,711	1,472	6,183	7.9
Buffalo	2,172	903	3,075	6.5
Cambridge	501	197	698	6.3
Chicago	7,878	5,298	13,176	5.1
Cincinatti	1,897	366	2,263	5.4
Cleveland	3,054	1,351	4,405	5.4
Columbus	726	212	938	4.2
Dayton	527	221	748	5.7
Fall River	766	136	902	7.0
Grand Rapids	96	248	344	2.5
Indianapolis	174	975	1,149	4.0
Jersey City	303	671	974	3.1
Kansas City, Mo.	1,461	766	2,227	7.1
Los Angeles	2,636	557	3,193	5.6
Louisville	150	1,056	1,206	5.0
Lowell	174	521	695	6.4
Memphis	152	655	807	5.2
Milwaukee	339	1,247	1,586	3.5
Minneapolis	1,099	194	1,293	3.4
Nashville	640	254	894	7.5
Newark	1,489	1,086	2,575	6.0
New Haven	914	227	1,141	7.4
New Orleans	2,199	1,114	3,313	8.7
New York	15,449	16,511	31,960	6.1
Oakland	975	259	1,234	5.8
Omaha	955	178	1,133	5.8
Philadelphia	8,807	6,759	15,566	8.8
Pittsburgh	2,545	3,153	5,698	9.6
Providence	1,091	531	1,622	6.2
Richmond	691	304	995	6.2
Rochester	1,002	272	1,274	4.8
St. Louis	2,188	1,425	3,613	4.6
St. Paul	894	197	1,091	4.2
San Francisco	3,192	593	3,785	7.9
Syracuse	833	194	1,027	6.4
Toledo	567	318	885	3.4
Washington, D.C.	2,294	822	3,116	7.8
Worcester	941	286	1,227	7.1

As a rule the intensive period in which the causative agent and secondary invaders infected with great virulence was comparatively short--in most instances from one to two weeks--after which milder cases apparently less liable to dangerous or fatal complications were encountered.

Charts Nos. 11, 12, 13, and 14 show the numbers of cases and numbers of deaths by days during the primary epidemics at the United States Naval Training Station, Great Lakes, Ill., United States Naval Training Camp, Pelham Bay Park, N.Y., marine barracks, Quantico, Va., and the United States Naval Treaining Camp, Cape May, N.J. The relation between morbidity and mortality curves varied widely at different stations, as indicated by the charts.

The tendency for sporadic cases to appear daily or frequently for some time after the subsidence of the outbreak was very common in all naval districts. As in numerous cities of the United States, there was a tendency in many naval stations toward a secondary or recurrent

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CHART 11.--Logarithmic scale, United States Naval Training Station, Great Lakes, Ill.: Influenza epidemic; case incidence and deaths by days.

CHART 12.--Logarithmic scale. United States Naval Training Camp, Pelham Bay Park, New York: Influenza epidemic; cases incidence and deaths by days.

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CHART 13.--Logarithmic scale. United States Marine Barracks, Quantico, Va.: Influenza epidemic; case incidence and deaths by days.

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outbreak within a few weeks after the principal epidemic had passed. In some instances, particularly in the more fulminating types, the epidemic had two peaks two or three days apart. Daily incidence curves for different stations show considerable variation from one another, and many epidemiological factors were operative to account for this; the more or less widespread occurrence of influenza in epidemic form during the preceding spring months, the varied nature of naval activities at different stations, size and character of the complement, density of population and character of housing, geographical location and the nature of the extra-naval environment. That the last factor was of importance is shown by the general similarity between the epidemic in the naval station and the epidemic in the city constituting its environment, although there were exceptions of course. For example, in New York City the epidemic was delayed in onset and the death rate was lower than in several of the other principal cities. Outbreaks in naval stations in and around Greater New York also came later and were somewhat less severe with regard to attack reates and case-fatality rates than those in stations located in Boston, Philadelphia, Norfolk, Pensacola, New Orleans, and Chicago.

CHART 14.--Logarithmic scale. United States Naval Training Camp, Cape May, N.J.: Influenza epidemic; case incidence and deaths by days.

Epidemics in the fleet.--Epidemics began in the Atlantic (battleship) Fleet about September 15, reaching their peaks in most instances in about 10 days, but outbreaks began on various transports early in September; in five, during the first week of September.

A study of epidemics in ships of the Navy shows that with a very few exceptions the personnel afloat suffered much less during the pandemic than the personnel ashore in spite of the fact that almost all ships of the Navy were much overcrowded and the crews of transports

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were exposed to epidemic conditions incident to outbreaks of influenza in highly virulent form among troops in transit. As a rule, the epidemic attack rate on board ship was comparatively low, averaging 16.3 per cent for battleships, 11.4 for cruisers, 29.4 for gunboats, 26.2 for submarines and destroyers, 8.8 for transports and 11.7 for miscellaneous vessels.

The U.S.S. Pittsburgh, an armored cruiser, was an exception. She encountered the disease in its most virulent form at Rio de Janeiro just as it was mounting to the peak of one of the worst of municipal epidemics. During the first seven days of the epidemic on board the Pittsburgh 48.7 per cent of the crew were attacked and for the whole period of the epidemic including mild cases which were not formally admitted to the sick list, the epidemic attack rate was approximately 80 per cent. This epidemic began October 7, reached its peak six days later with the admission of 211 cases that day, and subsided abruptly, only 4 cases occurring the next day and but 43 more in the following month and half. Six hundred and forty-seven cases were admitted to the sick list. Of these, 58 or 8.9 per cent died. The U.S.S. Yacona furnished another exception. Of her personnel, 95 in number, 80 or 84 per cent were attacked in the period between November 17 and 29. This was well after epidemics in New England had subsided. The Yacona encountered the disease at New London, Conn.

The relatively low incidence and low epidemic mortality rates among the personnel on board ship are in general agreement with similar epidemiological findings in the Navy for the 1889-90 pandemic.

Statistics relating to epidemics of influenza for certain vessels of the Navy are shown in table 7 which contains data collected by the fleet surgeon, United States Atlantic Fleet.

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A report submitted by the force medical officer, Cruiser and Transport Force, contains data for a few more transports than are included in the above table. The figures are as follows:

	Number of men.	Number of cases of influenza.	Percentage attacked.	Number of death.	Epidemic death rate per 1,000	Case-fatality rate per cent.	Number of cases of complicating pneumonia.	Percentage of cases complicated by pneumonia.
Transports:
Troops	1129,364	11,385	8.80	733	5.66	6.43	1,040	17.9
Crew	23,833	2,123	8.88	42	1.75	1.50	141	6.6

¹ Includes 5,638 marines.

29 December 2005