546 DISEASES OF THE HOESE. 



days, until the virulent matter which will prbduce ra-bies in anj 

 unj)rotected animal can be inoculated with impuhity. A curious 

 result of tlie experiments of M. Pasteur is that an animal which has 

 first been inoculated with a virus of full stren^h can be protected 

 by subsequent inoculations of attenuated virus repeated in doses of 

 increasing strength. 



Symptoms. — From the moment of inoculation by the bite of a rabid 

 dog or other rabid animal or by other means, a variable time elapses 

 before the development of any symptoms. This time may be eight 

 days or it may be several months ; it is usually about four weeks. 

 The first sym^Dtom is an irritation of the original wound. This 

 wound, which may have healed completely, commences to itch until 

 the horse rubs or bites it into a new sore. The horse then becomes 

 irritable and vicious. It- is especially susceptible to moving objects; 

 excessive light, noises, the entrance of an attendant, or any other dis- 

 turbance will cause the patient to be on the defensive. It apparently 

 sees imaginary objects; the slightest noise is exaggerated into threat- 

 ening violence; the approach of an attendant or another animal, 

 especially a dog, is interpreted as an assault and the horse will strike 

 and bite. The violence on the part of the rabid horse is not for a 

 moment to be confounded with the fury of the same animal suffering 

 from meningitis or any other trouble of the brain. But in rabies 

 there is a volition, a premeditated method, in the attacks which the 

 animal will make, which is not found in the other diseases. Between 

 the attacks of iury the animal may become calm for a variable period. 

 The writer attended a case in which, after a violent attack of an hour, 

 the horse was sufficiently calm to be walked 10 miles and only 

 developed violence again an hour after being placed in the new stable. 

 In the period of fury the horse will bite at the reopened original 

 wound ; it will rear and attempt to break its halter and fastenings; it 

 will bite at the woodwork and surrounding objects in the stable. If 

 the animal lives long enough it shows paralytic symptoms and falls to 

 the ground, unable to use two or more of its extremities, but in the 

 majority of cases, in its excesses of violence, it does physical injury to 

 itself. It breaks its jaws in biting at the manger or fractures other 

 bones in throwing itself on the ground and dies of hemorrhage or 

 internal injuries. At times throughout the course of the disease there 

 is an excessive sensibility of the skin which, if irritated by the touch, 

 will bring on attacks of violence. The animal may have appetite and 

 desire water throughout the course of the disease, but -on attempting 

 to swallow has a spasm of the throat, which renders the act impossible. 

 This latter condition, which is common in all rabid animals, has given 

 the disease the name of hydrophobia (fear of water). 



In a case under the care of the writer a horse, four weeks after 

 being bitten on the forearm by a rabid dog, -developed local irritation 

 Digitized by Microsoft® 



