CHAPTER XXV. 



CONTAGIOUS DISEASES— contimted. 



CANINE DISTEMPER. 



Definition. — A febrile disease, due to the operation of a morbid 

 poison, as the result of contagion and infection, and known in 

 almost all parts of the world. The specific microbe has not 

 been discovered, but it is known that the disease is transmissible 

 by contagion and infection, and that, therefore, the virus is both 

 volatile and fixed. It is most readily conveyed by the air. 

 The virulence of the contagium contained in the discharges, the 

 blood, &c., is diminished if kept in a dry state for a time, but 

 congelation and dessication seem to exert no power over it. 



PATHOLOGY. 



The virus primarily induces a febrile condition of the system, 

 and specifically affects the mucous membranes of the nose and 

 eyes. In some cases the poison destroys by shock, the animal 

 dying, in a few hours, from collapse, without any true signs of 

 distemper being developed. In other cases the action of the 

 poison is concentrated upon the nervous system, causing epilep- 

 tic fits, spasms of various muscles, and finally coma and death. 

 Again, the liver seems to be the organ chiefly affected, and in 

 other instances the intestinal canal or the bronchial mucous 

 membrane is the seat of the local effects of the virus. 

 Secondarily, the spinal cord or some of the spinal nerves become 

 diseased, and, consequently, distemper often terminates in para- 

 lysis of the posterior extremities, or in chorea ; the clonic spasm 

 characteristic of chorea being generally more observable in the 

 muscles of the neck and fore extremities. In consequence of 

 the variety of forms which the malady assumes, it has been 



