DISEASES OF HORSES 39 



stable for a considerable time, and if these are removed to other locali- 

 ties it may be carried in them. It may be carried in the clothing 

 of those who have been in attendance on horses suffering from the 

 disease. 



Symptoms. After the exposure of a susceptible horse to infec- 

 tion a period of incubation of from four 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 in- 

 tense 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 a 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 and rapid circulation and defective nutritive and reparative 

 functions. 



The first symptoms are those of a rapidly developing fever, 

 which becomes intense within a very short period. The animal be- 

 comes dejected 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, and frequently a grinding of the teeth which warns one 

 that a severe attack may be expected. The hairs become dry and 

 rough and stand on end. The body temperature increases to 104, 

 104.5, and 105 F., or even in severe cases to 107 F., within the 

 first twelve or eighteen hours. The horse becomes stupid, stands 

 with its head hanging, the ears listless, and it pays but little attention 

 to the surrounding attendants or the crack of a whip. The stupor 

 becomes rapidly more marked, the eyes become puffy and swollen 

 with excessive lachrymation, so that the tears run from the internal 

 canthus of the eye over the cheeks and may blister the skin in its 

 course. The respiration becomes accelerated to twenty-five or thirty 

 in a minute, and the pulse is quickened to seventy, eighty, or even 

 one hundred, moderate in volume and in force. There is great de- 

 pression of muscular force ; the animal stands limp, as if excessively 

 fatigued. There is diminution, or in some cases total loss, of sensibil- 

 ity of the skin, so that it may be pricked or handled without attract- 

 ing the attention of the animal. On movement, the horse staggers 

 and shows a want of co-ordination of all of the muscles of its limbs. 

 The senses of hearing, sight, and taste are diminished, if not entirely 

 abolished. The visible mucous membranes from which it is known 

 as the pinkeye, and the mouth and the natural openings become of 

 a deep saffron, ocher, or violet-red color. This latter is especially 

 noticeable on the rim of the gums and is a condition not found in any 

 other disease, so that it is an almost diagnostic symptom. In some 

 outbreaks there is much more swelling of the lids and weeping from 



