XXV. NEW CONTRIBUTION TO THE STUDY OF SEN- 

 SITIZERS FOR TUBERCLE BACILLI.* 



By DR. O. GENGOU. 



Bordet and Gcngouf showed that guinea-pigs inoculated with 

 virulent human tubercle bacilli die without forming any sensi- 

 tizers for this bacillus, but if, on the contrary, they receive an 

 injection of living avian tubercle bacilli, for which organisms they 

 are usually resistant, they form sensitizers that act not only on 

 the avian bacillus, but also on the human bacillus. Later on, 

 DembinskiJ stated that the living human bacillus produces no 

 sensitizer cither in the rabbit or in the pigeon, and he concludes 

 "that the production of sensitizers for tubercle bacilli does not 

 depend on the greater or less resistance of the animal employed 

 against these bacilli," as Bordet and Gengou believed, "but is 

 related to the type of bacilli employed." 



In the course of studies on experimental tuberculosis, we have 

 had occasion to control Dembinski's results. Since guinea-pigs 

 succumb to an inoculation of virulent human bacilli without pro- 

 ducing sensitizers, we used killed human bacilli (heated for one- 

 half hour to 65 degrees or for 5 minutes to 100° C). For compari- 

 son we gave other guinea-pigs injections of avian bacilli killed 

 in the same manner. Similar injections were also made in rabbits. 

 The animals were all immunized on three successive occasions 

 by subcutaneous injections at intervals of 3 weeks; they were bled 

 2 or 3 weeks after the last injection. 



We determined the presence of sensitizers in the serum of these 

 animals by the Bordet-Gengou method based on the characteristic 



* Nouvelle contribution al'etude des sensibilisatrices des bacilles tuberculeux. 

 Comptes Rend, de la Soc. de Biol., LVIII, 1906, 218. 



t Gengou, p. 462. Comptes Rendus de l'Acad£mie des Sciences. 

 % Dembinski, Soci6te de Biologie, 1901. 



464 



