478 



rnnning water may hold the virus aud be a means of its communication 

 to other animals even at a distance. The studies of Dieciierhoff, in 

 1881, in regard to the contagion of influenza were especially interest- 

 ing. He found that daring a local enzootic, produced by the introduc- 

 tion of horses suffering from influenza into an extensive stable other- 

 wise perfectly healthy, that the infection took place in what at first 

 seemed to be a most irregular manner, but which was shown later to be 

 dependent on the ventilation and currents of air through the various 

 buildings. His experiments showed that the virus of influenza is ex- 

 cessively diffusible, and that it will si^read rapidly to the roof of a build- 

 ing and pass by the apertures of ventilation to others in the neighbor- 

 hood. The writer has seen cases spread through a brick wall and attack 

 animals on the opposite side before others even in the same stable were 

 affected. Brick walls, old woodwork, and the dirt which is too fre- 

 quently left about the feed boxes of a horse stall, will all hold the con. 

 tagion for some days, if not weeks, and communicate it to susceptible 

 animals when placed in the same locality. A four-jear old colt, belong- 

 ing to the writer, stood at the open door of a stable where two cases of 

 influenza had developed the day before, fully 40 feet from the st<dl, for 

 about' ten minutes on two successive mornings, and in six days devel- 

 oped the disease. On the morning when the trouble in the colt was 

 recognized it stood in an infirmary with a dozen horses being treated 

 for various diseases, but was immediately isolated 5 within one week 

 two-thirds of the other horses had contracted the pink-eye. 



Symjytoms. — After the exposure of a susceptible horse to infection a 

 period of incubation of from five to seven days elapses, during which the 

 animal seems in perfect health, before any symptom is visible. When 

 the symptoms of influenza develop they may be intense or they may be 

 so moderate as to occasion but little alarm, but the latter condition 

 frequently exposes the animal to use and to the danger of the exciting 

 causes of complications which would not have happened had the animal 

 been left quietly in its stall in place of being worked or driven out to 

 show to prospective purchasers. The disease may run its simple course 

 as a specific fever, with alterations only of the blood, or it may become 

 at any period complicated by local inflammatory troubles, the gravity 

 of which is augmented by developing in an animal with an impoverished 

 blood and already irritated aud rapid circulation and defective nutritive 

 aiid reparative functions. 



The first symptoms are those of a rapidly developing fever, which 

 becomes intense within a very short period. The animal becomes de- 

 jected and inattentive to surrounding objects; stands with its head 

 down, and not back on the halter as in serious lung diseases. It has 

 chills of the flanks, the muscles of the croup, and the muscles of the 

 shoulders, or of the entire body, lasting from fifteen to thirty minutes, 

 aud frequently a grinding of the teeth which warns one that a severe 

 attack may be expected. The hairs become dry and rough and stand 



