TUBERCULOSIS IN THE DOG. 24I 



cases the characteristic temperature reaction had then passed. From 

 the temperature charts of forty animals injected with tubercuhn, I have 

 found that the maximum reaction occurs between the fourth and eighth 

 hours. In general it is quite distinctive. With doses of 5 to 10 centi- 

 grammes of tuberculin the temperature rises from 1° to 3° C. Tuber- 

 culous cases, however, do occur, especially among animals which are 

 very feeble or affected with generalised lesions, in which the reaction is 

 trifling or nil. Quite recently I saw a Danish boarhound, still in fairly 

 good health, but proved by subsequent post-mortem examination to be 

 distinctly tuberculous, which did not react in the smallest degree 

 to two injections of tuberculin, although the initial temperature was on 

 the first occasion 38° C. (ioo"4° F.), and on the second 38*3° C. 

 (100-9° F.). 



How does the dog contract tuberculosis ? One fact at least 

 appears certain, viz. that canine tuberculosis is of human origin. The 

 numerous inquiries I have made leave no doubt on this point. Either 

 the animal belonged to a phthisical patient or associated with a tuber- 

 culous person with whom it passed a portion of the day, or it accom- 

 panied its master daily to the wine-shop or eating-house — places where 

 in very many instances the floor is soiled with sputum containing 

 bacilli. 



In the dog, also, there are two principal avenues of infection, the 

 digestive and the respiratory mucous membranes. At first sight, having 

 regard to the extreme frequency of pulmonary lesions and the diffi- 

 culty of transmitting tuberculosis to the dog by ingestion of virulent 

 material, it seems, as Straus has remarked, that infection occurs often- 

 est by the respiratory passages, in consequence of the dog inhaling 

 infected dust. This is also the opinion I emitted in my work in 1893, 

 but despite the negative results of experiments in which dogs were 

 caused to ingest tuberculous material, despite the common absence of 

 lesions indicating the passage of bacilli from the intestinal mucous 

 membrane, and from the lymphatic glands originating there ; finally, 

 despite the predominance of pulmonary lesions, infection is caused at 

 least as often by the ingestion of virulent material as by the inhalation 

 of infective dust. 



We know that many dogs have a propensity to lick up human sputa ; 

 some will even go to the spittoons. In 1893 I made the post-mortem 

 examination of a young dog which became tuberculous under the follow- 

 ing circumstances : — Its master, M. V — , living in the Boulevard de 

 Picpus, in Paris, became affected with pulmonar}- tuberculosis. The 

 doctor who treated him recommended the use of a special recipient for 



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