Equine Influenza. Adynamic Catarrhal Fever of Solipeds. 153 



Inoculation. Experimental inoculations have transmitted the 

 disease with difficulty and uncertainty. Those of Hertwig, 

 Nocard, Arloing, I^abat, 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 ap- 

 parently 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 dis- 

 ease, 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, transmit- 

 ted 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 

 lyignieres. 



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 show- 

 ing 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-pneu- 

 monia, and at times intestinal or meningeal congestion. But 

 there is no proof that the malady so caused, passed with the cer- 

 tainty 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 Pas- 

 teurella of Trevisan. This group includes the non-motile germs 

 of swine plague, the septicaemic pneumo-enteritis of sheep, wilde- 



