118 Chapter V 



contains antifixative. The difference between the antispermotoxic 

 serum obtained by Metalnikoff and that prepared by me is similar 

 to that observed between the antihaemotoxic serums. Some contain 

 only anticytase but others undoubtedly contain antifixative also. 



As this result appeared to me to be of far-reaching importance I 

 felt bound to verily it by another method. I injected certain rabbits 

 with spermotoxic serum of the guinea-pig and others with normal 

 guinea-pig's serum. The amount of cytases being about the same in 

 both, the strength of the serums obtained as the result of injections 

 of normal serum and of specific serum should be the same if the 

 antispermotoxic serums contain anticytase only. Experiment demon- 

 strates just the contrary. The autispermotoxic serum of rabbits 

 treated with normal guinea-pig's serum was on every occasion much 

 [126] less active than the serum of rabbits injected with the spermotoxic 

 serum of prepared guinea-pigs. The former contains anticytase only, 

 whilst the latter contains in addition antifixative. Weichhardt's 1 

 experiments carried out in my laboratory corroborated the con- 

 clusion I have just formulated. 



Having made ourselves acquainted with the constitution of the 

 auticytotoxins we may now pass to the question of the origin of these 

 bodies and of analogous ferments which act in the resorption of 

 albuminoid substances in the blood and in the tissues. 



We have already mentioned that the leucocytes are charged with 

 a soluble ferment which digests gelatine, and that in animals treated 

 with injections of gelatine these cells elaborate a much larger amount 

 of the ferment. Here we have evidence of a kind of education of the 

 leucocytes to produce a greater amount of digestive ferment, in a 

 manner quite analogous to that which has been described in Chapter 

 III in connection with the augmentation of the pancreatic ferments 

 in intestinal digestion. It is, then, quite permissible to look upon 

 leucocytes, and probably phagocytes in general, as the source of the 

 soluble ferment that digests gelatine. 



Is this the case with the other substances which take an active 

 part in the resorption of albuminoid substances in the fluids and 

 tissues of the organism? Up to the present the origin of precipitins 

 and antiferments, such as antirennet, has not been studied. The 

 problem being very complex and difficult, it appears to be impossible 

 at present to solve it It is known indeed that the introduction of 

 these substances into the organism provokes a reaction similar to the 

 1 Ann. de CInst. Pasteur, Paris, 1901, t. xv, p. 833. 



