Part 20

First week in December. Cairo, Ill.; Lincoln, Omaha, Nebraska City, Neb.; Yankton, (5th), Vermilion, Dak.; Tallahassee, Fla.; Camden, Ark.; St. Louis, Kansas City, Mo.

Second Week in December. Quincy, Ill. (8th); Shreveport, La.; Hanibal, Mo.; Fort Scott, Lawrence, Leavenworth, Topeka, Kan.

December after the Second Week. Denver, Central City, Col.; Cienfuegos, Cuba.

January 1873. San Antonio (3d) Tex.; Cheyenne, Wyo.; Cimarron, (1st week), Elizabeth City (2d week), Alberquerque (4th week), N. M.; Salt Lake City, (2d week), Corrinne (3d week), Utah; Santiago, Cuba.

February. Brownsville (3d week) Tex.; Winnemucca, Nev.; Monterey (1st week), Mex.

March. Prescott (1st week), Tucson (2d week), Yuma (4th week) Ariz.; Boise City, (3d week), Ida.; Helena (4th week) Mont.; Virginia City, (1st week), Nev.; Carson City, Nev., Santa Barbara, Visalia, Cal.; Guaymas, Mazatlau, Manzanillo, Mex.

April. San Diego (1st week), Mariposa, Stockton, San José, Oakland, Sacramento, Marysville and Shasta (2d week), San Francisco, Vallejo, Nevada City and Weaverville (3d week), and Lava Beds, Cal. (4th week); Baker City (2d week), Jacksonville, Ore. (4th week); Walla Walla, Wash. (4th week); Acapulco (1st week), Mex.

May. Eugene City, (3d week), Dallas and Portland, Ore. (4th week); Olympia, Wash.

June. Seattle, Wash. (3d week).

July. Guatemala City, Guatemala (2d week), Victoria, B. C.

August. La Union, San Salvador (1st).

Among the deductions from this record are:

1. The affection advanced gradually from Toronto over the whole continent of North America, where horses are kept, taking full ten months to accomplish this. Nothing checked its advance, over lowland and highland, swamp and arid land, in summer as in winter, with a temperature at 0° or at 100° F., in country pasture or in city street or stable, idle or overworked, on all kinds of soils and geological formations, under all successive conditions of meteoric and terrestrial electricity, in all conditions of the air—pure, impure, dense, light, moist and dry. No one condition of the environment operating on the animal system, can be conceived of that could advance as this disease did from place to place in regular sequence for this length of time.

2d. The rapidity of its progress was manifestly subordinate to the activity of the movement of the equine races from points already infected. Its most rapid advance was along the lines of railway while the back districts shut out from railway traffic were much later in being invaded. The larger cities situated on the through railroad routes suffered earlier than the smaller places on the same lines. The outbreak was several days earlier in Montreal than in the nearer and smaller cities of Kingston, Ottawa, Belleville, Port Hope, Peterboro, Stratford, Brantford, Guelph, London and Owen Sound. The important port of St. John, N. B., suffered two weeks earlier than Quebec. Along the N. Y. Central and Erie Railways etc., Boston and New York suffered nearly a week earlier than Utica, Poughkeepsie, Binghampton, Elmira, and Jamestown, while the smaller places like Kingston, Nyack, Ithaca, etc., were later still. In Baltimore the disease was seen a day earlier than in Philadelphia, and in these cities and Washington over a fortnight before it was seen in Scranton, Pa. So it was almost everywhere and in these large cities the outbreak could in nearly every case be traced to horses just arrived from a pre-existing centre of infection. In Detroit, Syracuse and Chicago it spread first in stables that had just received Canadian horses, in Ithaca in one which had received horses from an infected centre in Northern New York and in Pittsburgh and Washington in stables that had just admitted horses from infected New York.

3d. It advanced with much greater rapidity eastward than westward, being in the line of greatest horse traffic, the animals being mainly raised and fitted in the West and shipped in large numbers to the great cities near the Atlantic seaboard.

4th. In the absence of this active railway traffic In horses, the advance was most rapid through other lines. In Pa., in a number of valleys opening to the south, the disease reversed its general direction, and extended northward up these valleys. In Lehigh Co., Pa., it followed the course of the canal, being carried by horses and mules employed on the towpath. In Davidson and Sumner Cos., Tenn., it followed the track of a circus which came through an infected locality. It reached the Pacific coast at Santa Barbara (not at the railway terminus at San Francisco) having followed a mule stage route in the absence of an active, westward progress of horses by rail.

5th. The affection failed to overstep any serious gap over which there was no movement of equine animals. It prevailed in Victoria, B. C., in July, but, owing to a strict quarantine on horses and mules, it failed to reach Vancouver Island. It ravaged New Brunswick and Nova Scotia in November but failed to reach Prince Edward Island which was then ice bound and shut off from all traffic with the mainland. It ravaged Cuba to which it was brought by American horses landed at Havana, but no other West Indian island was attacked. Its southward course was finally arrested at Central America, where horses are few and horse traffic nearly unknown.

Every fact in connection with its eruption and progress agrees perfectly with the hypothesis of transmission by contagion alone, and taken altogether the history excludes all other causes from being anything more than accessory. Before the days of modern bacteriology we had ample proof that glanders, rabies, sheeppox, lung plague, and Rinderpest were due to contagion alone as an essential cause, and so now we have the same evidence concerning equine influenza.

Other testimonies to Contagion. Trasbot says the virulence is “almost equal to that of Rinderpest or aphthous fever,” and adds “all practitioners have become assured that the bringing of an affected animal into a stable constantly introduces the malady to the others.” Cadeac says “the diseased or infected animals are the main channel of propagation of the malady” and again the disease is “essentially infectious.” Friedberger and Fröhner are more definite—“influenza which is as highly infectious as any other disease can be produced only by infection.” Cadeac implies nearly as much in saying: “in all the epizoötics that have invaded Paris, the disease has been carried into the four quarters of France by horses bought in this city. In most regiments the malady shows itself after the arrival of horses from remounts where it was prevailing. At Sibourne it is through horses from St. Jean d’Angely. At Lyons it is by a horse from Cæn. At Bourges the source was not traced but it spread from the garrison to the whole surrounding country. The Omnibus stables in the Rue d’Ulm were invaded when a horse was introduced from Clichy where influenza raged.”

Stables are fruitful sources of infection hence dealers’ horses and horses travelling from place to place have long been objects of just suspicion (Trasbot, etc.).

Cars are often infected, and spread the disease widely. (Poucet, Salle, Trasbot, etc.).

Manure is especially dangerous. Trasbot gives a number of cases of the infection of farms, by the manure taken from the Alfort Veterinary College, and other infected stables in Paris. Friedberger conveyed the disease experimentally in the manure.

The conveyance of the virus on the clothes of attendants has been alleged by Friedberger and Fröhner, and considering that it has been noted to pass over intervals of about half a mile without the intervention of any horse, it must have been wafted on the air, or conveyed on the surface of man or non-equine beast.

Jensen and Clark allege that the contagium may be conveyed to mares by coition, for months after the stallion has shown all outward signs of recovery. This would be entirely in keeping with the analogous fact in swine plague.

Inoculation. Experimental inoculations have transmitted the disease with difficulty and uncertainty. Those of Hertwig, Nocard, Arloing, Labat, Friedberger, Trasbot, Pasteur and others came to naught. Even the transfusion of the blood of the sick, proved as harmless as the inoculation of the serous exudate. A probable explanation is found in the extreme diffusibility of the germ of equine influenza, which spreads over a city or county in a few days, attacking practically all equine animals. Inoculation is necessarily made at the time of the prevalence of influenza and at such a time all horses in a wide area are likely to be suffering from the affection. Those that are unaffected and therefore apparently available for experiment, are the immune animals. If they were susceptible the probability is that they would speedily show the disease through infection drawn from another source than the inoculation. If the inoculated animal failed to contract the disease, and yet very shortly afterward became infected by simple exposure, there would be some basis for alleging that inoculation was always inoperative. Dieckerhoff, on the other hand, transmitted the disease to healthy horses by subcutaneous and intravenous inoculation of the blood of the sick, and the same seems to be true of inoculations of the cultures of the cocco-bacillus by Lignieres.

Bacteriology. Our knowledge of the bacteria of equine influenza is as yet very imperfect and uncertain. Galtier and Violet found streptococci and diplococci in the blood and tissues of cases showing intestinal lesions, and held that they were derived from musty fodder. Injections of infusions of such fodder into the trachea of the horse produced broncho-pneumonia, double pleuro-pneumonia, and at times intestinal or meningeal congestion. But there is no proof that the malady so caused, passed with the certainty and rapidity of equine influenza from horse to horse in the same stable.

The cocco-bacillus found by Lignieres in the blood and exudate of the patients has more plausible claims to being the specific germ. This is an ovoid bacterium, somewhat smaller than that of chicken cholera, and like it pigmented at the poles and clear in the central part, a characteristic feature of the group of Pasteurella of Trevisan. This group includes the nonmotile germs of swine plague, the septicæmic pneumo-enteritis of sheep, wildeseuche, and septicæmia of rabbits and chickens, as well as that of fowl cholera; all stain easily in gentian violet and fuchsin, and all cause some form of hemorrhagic septicæmia. The germ is ærobic and grows best in peptonized bouillon to which a little serum has been added. It forms, in peptonized gelatin, round colonies, at first transparent and later opaque or milky, and without liquefaction. The cultures when inoculated subcutaneously proved fatal to Guinea pig, rabbit, rat, mouse, dog, cat, sheep, pig, ox, ass, pigeon and chicken.

Intravenous inoculation on the horse of 1 to 2cc. of the culture kills in a few hours, the temperature having risen to 104° F., the mucosæ acquire a dull brown tint, the eyes are swollen and weeping, enteritic colics appear, the limbs may swell and there may be painful arthritis and jaundice. At the necropsy the blood is black and incoagulable, the muscles as if parboiled, the liver a deep violet, the intestinal mucosa congested, a yellowish or reddish effusion in the pericardium and numerous petechiæ on the serosæ.