GENERAL DISEASES. 189 



by the powers of digestion. If recovery is slow tonics are indicated, cod 

 liver oil will prove especially valuable. The different complications will 

 be found elsewhere considered as distinct diseases. 



DIPHTHERIA. 



While diphtheria is an affection which very rarely attacks dogs, the fact 

 that it has been observed among them renders a brief description war- 

 rantable. 



It is a disease which invades especially the membrane of the air pas- 

 sages, and general infection follows the local expression. The local disease 

 appears as an inflammation of the mucous membrane, especially of the 

 mouth, pharynx, nose, larynx, and deeper air passages, and precedes the 

 formation of a greyish-white membranous exudation. 



The constitutional affection has the character of infectious diseases, and 

 is essentially the same as in all dependent upon blood poisoning. The 

 problem is still unsolved whether diphtheria is at first a general disease, 

 and poisoning of the blood and the local affections of the mucous mem- 

 brane are secondary manifestations, or whether the disease begins by 

 local infection, from which point the poison is taken into the system and 

 the whole organization becomes contaminated. 



It is generally accepted that the germ of the disease first fixes itself upon 

 a certain part of the body, more often the mucous membrane, and there 

 at its point of attachment it excites a local affection, then through absorp- 

 tion the poison penetrates the tissues and is soon carried throughout the 

 whole body. 



Diphtheria is an epidemic disease, and like all others has an especial 

 cause, a contagious virus or infectious miasm. Certain conditions favor 

 the propagation of the disease ; impure air and poisonous exhalations 

 from decomposing filth are important factors in its production. Among 

 the reported cases of the disease among dogs, it is observed that the onset 

 in some was marked by great febrile disturbance ; in others the constitu- 

 tional symptoms were less severe. In the larger proportion the disease 

 attacked the mucous membrane of the throat, and more rarely were the 

 nasal passages first involved. In the former the throat presented a dark 

 red, swollen, glistening appearance ; the glands of the neck being en- 

 larged and tender, and swallowing difficult. In some instances ulcers 

 were seen on the tonsils. 



When the disease assumed a concealed or nasal form, it manifested 

 itself by general depression, fever of a low type, and a thin, reddish, 

 Offensive discharge from the nose. The glands of the neck were swollen 



