MECHANISM OF PROTEIN HYDROLYSIS AND IMMUNIZATION 39 



evidence of the validity of (1) the general thesis that the cor- 

 puscles deal with foreign proteins, and (2) the important feature 

 of the theory which ascribes to the red corpuscles the work of 

 ultimate proteolysis and oxidation of the split molecules of the 

 order of polypeptids. 



The experiments that (if I correctly interpret them) throw 

 corroborative light on the first-mentioned aspect of the Proteo- 

 morphic theory were made by Drs. M. W. Man waring and Yoshio 

 Kusama, of the Department of Bacteriology and Immunity of 

 Leland Stanford, Jr., University, as recorded in the Proceedings 

 of the Society for Experimental Biology and Medicine, of May 

 24, 1916. These experiments go to show that the blood corpuscles 

 of a rabbit actively absorb goat serum proteins, whether the goat 

 serum is mixed with the (defibrinated) rabbit's blood in a recep- 

 tacle outside the body or whether it is injected into the system of 

 the living rabbit. 



This observation, obviously, gives the strongest support to the 

 assumption of the Proteomorphic theory that the blood corpuscles 

 are the agents chiefly concerned in dealing with foreign proteins ; 

 the assumption that forms the chief basis for the explanation of 

 the therapeutic action of the proteal remedies with which the 

 present monograph is concerned. 



It should be added that, in the experiments just cited, it is 

 further recorded that about 25 per cent, of the goat protein may 

 remain in the rabbit's blood serum. "If the serum and cor- 

 puscle fractions (of the blood), are allowed to undergo inde- 

 pendent autolysis (10 hrs., 37 C.) a distinct restoration of the 

 goat protein is observed in each fraction. The restoration of 

 the protein in the corpuscle fraction, however, is usually much 

 more pronounced than that in the serum fraction, and may amount 

 to as much as 50 per cent, of the total protein originally added to 

 the blood." 



From this it would appear that something like 25 per cent, 

 of the goat serum originally injected is unrecovered, presumably 

 having been hydrolyzed to a stage of decomposition at which 

 it is no longer recognized as goat protein. 



It would appear to be a logical inference that such hydrolysis 

 of the goat serum proteins has been effected by enzymes gen- 

 erated in the bodies of the corpuscles which, according to the 

 observations of the experimenters, constituted the chief medium 

 for absorption of the foreign proteins. As far as they go, these 

 experiments afford direct collaboration of one of the principal 

 theses of the proteomorphic theory. 



Possibly it may seem surprising that so large a proportion of 

 the goat serum proteins remained unhydrolyzed after 10 hours' 

 maceration. It must be obvious, however, that corpuscles under- 



