462 GENEEAL DISEASES. 



there seems to be no connection between outbreaks of influenza 

 among men and those among horses. Pfeiffer set up influenza in 

 rabbits by applying to the nasal mucous membrane of these 

 animals, the genus which he had obtained from influenza-infected 

 men. The human influenza bacillus requires a certain amount of 

 moisture for its existence and development. 



Influenza being hig'hly infectious, spreads, as a rule, with great 

 rapidity. 



Williams considered that the outbreak of this epizootic which 

 affected a great number of horses in Edinburgh and the sur- 

 rounding districts, during the months of January and February, 

 1877, was due to the saturation of the ground with water, owing 

 to long continued wet weather; and advanced the fact, in support 

 of this statement, that cases were, comparatively, very rare in 

 stables, the floors of which were waterproof on account of being 

 covered with cement. This bears out the theory that the microbe 

 of equine influenza, like that of human influenza, develops best 

 under conditions of moisture. It has not unfrequently happened, 

 that stables for which influenza has shown a marked partiality, 

 have been rendered sanitary, by taking up the flooring, and put- 

 ting it down afresh, and by carefully draining the building. 



The mode by which the influenza of the horse is propagated is 

 entirely unknown. Trasbot states that he has often tried to pro- 

 duce the disease by inoculating with the blood, with the discharge 

 from the nose, and with other products ; but always in vain. 



For safety's sake, it is well to isolate, for at least a week, even 

 apparently sound horses which have been recently brought from 

 districts in which influenza is rife, before they are allowed to 

 enter stables containing healthy horses. 



Stallions which have had influenza, sometimes remain capable 

 of infecting mares they cover, for several months after they have 

 apparently regained perfect health. 



Although the type of influenza varies greatly, both in individual 

 cases and in different outbreaks ; the cause of the disease appears 

 to be the same in all, however dissimilar may be its manifestations. 

 Symptoms of catarrh may be prominent in one case, or in one 

 epizootic; those of bowel disorder in another; and symptoms of 

 rheumatism may manifest themselves indiscriminately. 



VARIETIES. —Influenza may be roug'hly divided as follows: — 

 (1) simple catarrhal influenza; (2) pink-eye; (3) abdominal or en- 

 teric influenza; (4) rheumatic influenza. 



Some authorities consider that when the mucous membrane which 

 lines the eyelids, presents a pink appearance, the disease is a dif- 

 ferent one from the simple catarrhal form ; while others hold that 



