The troop ship "Himalaya" arrived on January 30 at the uninfected harbor of Colombo (Ceylon) with 19 cases of influenza on board (during the voyage 140 cases had occurred). On February 7 the epidemic broke out in the harbor, first among the pilots employed there.
It is worthy of mention that influenza did not break out on ships in an explosive manner, but became slowly disseminated. On several ships the epidemic lasted for many weeks.
In some few instances the duration of the epidemic on ships, for example, on the "Bellerophon," from March 27 to April 30; upon the " Canada," from the eleventh of April to the twenty fourth of May; upon the "Comus," from the tenth of April to the third of May, may be explained by the fact that the affected ships, which in the course of their voyage became free from the disease, arrived at infected ports, at which places they took up fresh influenza germs.
The German.marine report, in reference to the spread of influenza upon ships, sums up: "In'every case upon our ships the disease did not appear suddenly, but gradually; not until after the sixth day from the beginning of the epidemic did the cruiser "Schwalbe " have numerous cases on board."
We must not ignore the fact that in not a few cases the experiences of other ships were quite different from these, for, just as upon the land, in some cases the disease arose suddenly and with great vehemence. Upon this fact the upholders of the miasmatic theory lay great stress.
We will content ourselves by giving one example-the celebrated case of the frigate "Stag"; upon this ship, on the third of April, 1833, as it reached the infected coast of Devonshire and so "came within the land breezes," the epidemic arose suddenly with great vehemence. At 2 o'clock 40 men were sick; at 6 o'clock this number was increased to 60, and on the next day, at 2 o'clock, that is, within twenty four hours, 160 men were affected by the disease. In regard to this case, which is one of the favorite examples of the spread of influenza germs through the air, Parkes remarks very pertinently that the report is incomplete, in so far as it does not state that there had been no communication with land (Plymouth or Falmouth). Moreover, the direction of the wind as recorded does not correspond.
Upon the Netherland frigate in the harbor of Macassar (on the island of Celebes) an influenza epidemic arose in February, 1856, which "within a few days " affected 144 men out of 340 of the entire ship's crew. On the "Canopus " (650 men), which in 1837 was in the harbor of Plymouth, where influenza was present, on the fifteenth of February "two thirds of the entire crew were suddenly stricken with influenza." Upon the Swedish corvette "Saga," at the end of January, 1890, during the day, after the diseased had left the infected harbor of Havana, influenza arose suddenly with such vehemence as to almost bring about a catastrophe.
The morbidity upon ships of both the German and the English navies in general was slight. It was about 3 per cent, upon the "Benbow," belonging to the Mediterranean fleet; about 6 per cent, upon the "Im perieuse," etc. But there are many examples of a much higher morbidity, as of 60 per cent, upon the "Archer" and 57 per cent, upon the " Curacao."
More important than the observations mentioned above is the fact that in our latest influenza period, in spite of the development of facilities for obtaining news rapidly, no single example was brought to light of a ship upon the high seas becoming affected ex aere, without touching at infected harbors or coming in contact with infected ships. Several cases where this is said to have happened were mentioned in the last century (at first by Reaumur in 1732). These have attained a historic notoriety, and still serve as support for the upholders of the panaerodromic theory.
But all these cases, that of the "Atlas " (1780, in the China Sea), of Kempenfeldt's squadron (1782, off the Lizard lighthouse), of Lord Howe's fleet (1782, off the Dutch coast), of the frigate "Stag " (1833, off the English coast), of the " Arcona " and the "Ariadne " (1785, in the China Sea), cannot, as Parkes has shown, stand the test before strict criticism.
On this account the following case, which occurred in our most recent pandemic, deserves attention. Upon the French man of war "Du quesne," in February, 1890, fourteen days after leaving the harbor of Montevideo, while the vessel was upon the high sea (150 miles from the American and 700 miles from the African coast) and in fine weather, a most intense epidemic of grip arose; out of 580 of the crew, 233 were taken ill. Even although Montevideo was free from grip and was not, like Buenos Aires, Santos, etc., affected in the beginning of February with the disease, nevertheless the case of the "Duquesne" is interesting. The explanation of this case lies in one of two facts: Either there were mild influenza cases on board at the time of sailing which at first did not attract attention because they did not report themselves ill, or the germ was carried on board in merchandise, clothing, etc., which, when unpacked, fourteen days after leaving Montevideo, spread the disease on the ship.
The English marine report teaches us that the greater number of ships upon the ocean during the epidemic period of 1889-1891 suffered from influenza. This is easily explained. Infected ships communicated the disease to harbors at which they arrived, and ships previously free from influenza were there infected. The intercommunication of ships from harbor to harbor throughout the world makes a closed circle of mutual infection analogous to that resulting from railroad traffic on land.