Resot-ption of albuminoid fluids 123 



and young, sexually immature rabbits of both sexes, also react to 

 injections of spermotoxin by producing the corresponding antispermo- 

 toxin. The specific elements which are sensitive to the action of a 

 cytotoxin undoubtedly are not indispensable for the development of 

 the corresponding anticytotoxin. This result is in complete harmony 

 with the hypothesis above put forward, that the red corpuscles cannot [131] 

 be regarded as the source of the antihaemotoxin. In the case of anti- 

 spermctoxin this fact can be rigorously established by experiment. 



Here arises the following question. We have seen that the anti- 

 cytotoxins are composed of two different substances : an anticytase 

 and an autifixative. The former is an antitoxin capable of neutralising 

 macrocytase, the soluble ferment which will attack indifferently all 

 kinds of cell elements. It is not to be wondered at, then, that the 

 exclusion of the spermatozoa in no way prevents the production of 

 anticytase by an organism which receives injections of cytotoxins. 

 These latter, as we have already said, contain cytase along with the 

 specific fixative ; the macrocytase can attack any kind of animal cell 

 provided that it can find some fixative or any other means to penetrate 

 into the interior of these formed elements. We have seen that the 

 antispermotoxin, obtained by Metalnikoff in guinea-pigs, does not 

 contain any anticytase. Amongst his animals treated with spermo- 

 toxin was a castrated male guinea-pig which also produced anticytase. 

 There is nothing astonishing in this fact, the injected cytase must have 

 linked itself to many other cells which were able to develop anticytase. 



But the example of the antispermotoxin of the rabbits in my own 

 experiments is very different. In order that it might manifest its action 

 the serum of these rabbits did not need to be heated to 56 C. ; it was 

 not necessary to rid it of its own macrocytase which could have acted 

 under the influence of the fixative, if this latter for want of antifixa- 

 tive had remained free in the added spermotoxin. This antifixative, 

 then, is undoubtedly found in the serum of castrated males which have 

 shown themselves capable of producing not only anticytase, but also 

 antifixative. This result has been further verified by comparative 

 experiments on castrated male rabbits, some of which received 

 spermotoxic guinea-pig's serum whilst the others received only 

 normal guinea-pig's serum. It has been demonstrated that the 

 amount of cytases remains almost constant in both normal and 

 vaccinated animals 1 . If, then, the antispermotoxins contain only 

 1 Bordet, Ann. fo flmt. Pasteur, Paris, 1895, t ix, p. 499; von Dungern, 

 Munchen. med, Wchnschr., 1900, S. 678. 



