The Cy to toxins 133 



other reptile infected countries, as well as in zoological 

 gardens where venomous serpents are kept, and in labora- 

 tories where the snakes are kept for experimental purposes, 

 it is well to be provided with a supply of the serum, but it 

 has no wide sphere of usefulness. 



4. Miscellaneous anti -bodies of many kinds have been 

 experimentally produced, anti-enzymes, etc., but have 

 no practical application. A knowledge of them is, however, 

 essential to a thorough understanding of the reactions of 

 immunity. In the synopsis of the experiments upon im- 

 munity reference is made to the bodies, and to the literature 

 bearing upon them. 



IV. The Cytotoxins. These comprehend the bacterioly- 

 sins, hemolysins, spermotoxins, epitheliolysins, nephrotoxins, 

 etc. They appear after immunization against formed 

 elements, according to principles made clear in the section 

 explaining immunity. The reactions involved in their 

 operation result from the combination of the " amboceptor, " 

 "immune body," "substance sensibilisatrice," "fixateur," 

 or "desmon" with the "addiment," "complement," 

 ' ' alexin, " or " cytase . " It was at first hoped that bac terioly- 

 tic serums would have a wide therapeutic application in all 

 cases in which non-toxicogenic bacteria were invading the 

 body, but experiment and experience have shown that the 

 laws governing their action greatly limit their application, 

 and that their effects, when not beneficial, are bound to be 

 harmful. 



It has already been explained that when bacteria of any 

 kind are repeatedly injected into an animal, its serum soon 

 comes to contain a considerable number of haptophore 

 groups fitted to combine with micro-organisms of similar 

 kind and so make possible the action of the real destroying 

 substance, the complement. In this process, however, the 

 complement itself is not increased, so that the serum has in 

 itself scarcely any increase of bactericidal activity above the 

 normal, though it may serve to activate other serums not 

 normally active upon that bacterium. To introduce an im- 

 mune body into the blood of an animal suffering from an 

 infection of any kind is to do it little good, because in most 

 cases the existing infection has brought about the formation 

 of as much or more "immune body" than can be utilized by 

 the complement, and more cannot be utilized. To give it in- 

 jections of active bodies that cannot be utilized is shown by 



