250 Manual of Veterinary Microbiology. 



MM. Cadiot, Gilbert, and Roger by means of the gen- 

 eralized lesions which they obtained in two guinea 

 pigs with virus coming from the pheasant. After 

 three passages through mammals this virus was inocu- 

 lated without effect to two chickens. 



The injection into animals of tuberculin prepared 

 from the bacillus of fowls is followed by the same ef- 

 fects as the injection of tuberculin of human origin. 



We must therefore regard the bacilli of avian 

 tuberculosis and the bacilli of mammalian tubercu- 

 losis as varieties of the same species. 



Vaccination. — Tuberculosis is essentially a recurrent 

 disease; a first attack begets a predisposition to a 

 second. It seems, therefore, a priori, paradoxical to 

 endeavor to prevent it by means of culture products. 

 Nevertheless, MM. Richet and Hericourt, Courmont 

 and Dor, have succeeded in producing in the rabbit a 

 certain degree of immunity against tuberculosis by the 

 injection of sterilized cultures of the bacillus of avian 

 tuberculosis; they employed bouillon cultures and ob- 

 tained sterilization by heat or by filtration. The dis- 

 ease was retarded in the majority of the vaccinated 

 animals; in some it was completely prevented. These 

 results justify us in affirming the existence of vac- 

 cinating substances in cultures of the tubercle bacilli 

 and of indulging the hope that, some day, it may be 

 possible to vaccinate the human being against this 

 terrible disease. 



Vaccination experiments have been made in the 

 rabbit by means of the blood serum of the dog 

 (hsemocyne). The investigators who have taken the 

 initiative in these experiments seem to have obtained 

 if not absolute immunity at least a retardation of the 



