THE PARTIAL-FUNCTIONS OF CELLS. 681 



The actual independence of haptophore and toxophore groups was 

 conclusively demonstrated by the discovery of substances which 

 had the power to excite the production of antibodies, and which, 

 therefore, were antigens, without possessing any toxic action. I 

 may remind you of the precipitins first observed by Kraus, Tschis- 

 tovitsch and Bordet. These authors showed that albuminous bodies 

 derived from either animal or vegetable organisms were able to 

 excite the production of specifically reacting antibodies, and this 

 whether they possessed toxic properties or not. The demonstration 

 of their antigen nature was thus extended to true food- stuffs, a result 

 to be expected on the basis of my theory. Moreover, even among 

 the poisons found in nature, some have been encountered in which 

 the independence of the haptophore and of the toxophore apparatus 

 is at once recognized. I refer to cytotoxins which are found normally 

 in the blood serum of certain higher animals, or which can be artifi- 

 cially produced by immunization with any particular species of cell. 

 These cytotoxins differ from all other poisons known to us by the 

 extraordinary specificity of their action by a degree of monotropism 

 possessed, so far as we know, only by the poisons derived from the 

 living animal body. Owing to their complex constitution it is easy 

 to differentiate the haptophore and the toxophore apparatus, and 

 to show that ihe function of the distributive component, the ambo- 

 ceptor, is to concentrate the really active substance on the affected 

 cell. This is effected by an increase in the affinity of the amboceptor 

 after union with the cell has taken place. The fact that ani- 

 mal cells act as antigens without possessing any toxic action, and the 

 fact that it is possible to immunize with dissolved albuminous sub- 

 stances, demonstrates that only the haptophore group is responsible 

 for the formation of antibodies. 



The recognition and the careful analysis of the specific relations 

 existing between the haptophore groups of antibodies and of recep- 

 tors, has proven of the highest theoretical and practical importance 

 in serum diagnosis. To cite only a few examples, let me call your 

 attention to the determination of the agglutinating titer in its 

 application to the Widal reaction in typhoid fever, to the method 

 of differentiating albumins introduced by Wassermann and Uhlen- 

 huth, and its significance in the forensic diagnosis of blood, to the 

 measurement of the opsonic index introduced by Wright, and to 

 numerous applications which haVe been made of the method of 

 complement binding, a method whose scientific basis also rests 



