DIPHTHERIA TOXINE. 99 



Especial interest attaches to the question whether the anti- 

 toxine circulates as such in the blood, and, if so, whether it is 

 a proteid or not, or whether it enters into combination with a 

 definite proteid of the blood. This also involves the question 

 whether its precipitation together with proteid substances is 

 simply a mechanical carrying down, or whether the precipitation 

 is due to chemical reactions of a specific nature. 



It is undoubtedly very probable, a priori, that the antitoxine 

 is a proteid, since according to the theory it is a constituent of 

 the cell protoplasm. There is also absolutely no ground, as in 

 the case of toxines, for regarding the antitoxine as an agency 

 of enzymic character. On the contrary, it has absolutely no 

 action by itself, either toxic or fermentative, and only enters 

 into combination with the toxic ferment of bacteria, and it is 

 a quite unwarranted generalisation to transfer the enzymic 

 character of toxines to their antitoxines without further proof. 

 The antitoxine lacks, to retain the graphic mode of representa- 

 tion, every specific group with the exception of the haptophore 

 group, and thus has neither a toxophore nor a zymophore group; 

 it is indeed a haptine, but one that possesses only one, the 

 haptophore, group. In point of fact, there are many reasons 

 against the antitoxine being of an enzymic character. The 

 only real argument in support of that view is the fact that it 

 becomes inactive at 100 C., and that is surely not a sufficient 

 reason. Against this, and in support of the view that it is a 

 specific proteid, must be set the fact that it is not simply carried 

 down mechanically, like the enzymes, but that it shows well- 

 marked precipitation reactions. As has already been shown by 

 BRIEGER and BOER (loc. cit.), the antitoxine is only carried 

 down, together with zinc carbonate, when it has previously 

 been precipitated by means of zinc sulphate, and not when 

 zinc chloride has been used for the purpose. In like manner 

 FREUND and STERNBERG were able to demonstrate that the 

 antitoxine was not precipitated simultaneously with the slight 

 precipitates produced by alum in the serum, although these 

 carried down all albumins. 



It would appear, then, that the antitoxine either actually 

 enters into combination with one of the proteids of the blood, 

 or we must assume that the particular proteid of which the 

 antitoxine consists approximates so closely in its reactions to 

 a proteid of the serum that it is very difficult to distinguish 

 "between them. 



Quite recently, however, PROSCHER (loc. cit.) has stated that 

 he has prepared a diphtheria antitoxine which no longer shows 



