298 A CHEMICO-PHYSIOLOGICAL STUDY OP 



in his comparative study of the physiological action of pro- 

 peptone and peptone reached the following conclusions: A 

 second injection of propeptone is without effect on blood co- 

 agulation if it be carried out on an annual (dog) in which the 

 effect of a previous injection has just disappeared. This is 

 true, says Grosjean, even when the second injection is made 

 with a large dose of the propeptone. The immunity acquired 

 persists, for the most part, about twenty-four hours after the 

 primary return of coagulability, when the blood again becomes 

 coagulable; the time of coagulation not only returns to the 

 normal but may even be shortened. With reference to purified 

 peptone Grosjean concludes that the injection of this substance 

 may likewise confer immunity against subsequent injections 

 of both peptone and propeptone. 



Gley and Le Bas * have also carried out a series of experi- 

 ments on the behavior of the blood with reference to its 

 coagulability after repeated injections of Witte's "pepton." 

 As a result of their systematic study on a large number of 

 dogs they conclude that in general the period of time during 

 which the blood remains non-coagulable after a rapid injection 

 of proteoses increases with the dose of proteoses employed 

 per kilo of body-weight. Furthermore, the length of time 

 during which immunity to subsequent injections persists also 

 increases with the original dose. Thus, absolute immunity 

 persists after return of the blood to its normal coagulability, 

 about fifteen minutes for 0.01 gram per kilo, and about five 

 hours for a dose of 0.3 gram per kilo.f The investigations of 

 Gley and Le Bas thus fail to confirm current statements, 

 namely, that a preliminary injection of proteoses may confer 

 immunity for twenty-four hours toward subsequent injections. 



Arthus and Huber $ observed that preliminary injections of 

 gelatoses and caseoses were effective in preventing the anti- 

 coagulating effect of subsequent large doses of the same 



* Gley and Le Bas : Archives de physiologic, 1897, p. 848. The experi- 

 ments of Contejean (Ibid., 1895) are not referred to above since they have 

 only an indirect bearing on this subject. 



t Gley and Le Bas, loc. cit., p. 860. 



| Arthus and Huber, Archives de physiologic, 1896, p. 857. 



