606 BACTERIOLOG Y. 



simple receptor pairs with that of the intoxicant and a 

 physiologically inert complex results. He conceives 

 antitoxins to be simple receptors of this type, and 

 believes the neutralization of toxins by them to take 

 place in this manner. On the other hand, if the im- 

 munization of an animal is accompanied by an acquired 

 power on the part of its serum to disintegrate bacteria, 

 to dissolve alien erythrocytes, to digest such cellular 

 elements as epithelium and spermatozoa, to precipitate 

 milk, or agglutinate bacterial or blood-cells, as the 

 studies of Pfeiffer, Bordet, von Dungern, Moxter, Fish, 

 Belfonte and Carbon, Metchnikoff, Gruber, Durham, 

 Widal, and others, have demonstrated, then the process 

 becomes less simple, and the atomic grouping of the 

 receptive molecule is correspondingly more complex. 

 In some cases the receptor is provided with both a hap- 

 tophore and a ferment-like (zymophore) group ; the 

 function of the former being to combine with and hold 

 in close proximity to the latter the albumin molecule 

 that is to be destroyed or assimilated ; in this way 

 bringing and holding the albumin molecule directly 

 under the influence of the zymophore group. In other 

 cases the " receptor " functions symbolically, so to speak, 

 with a complementary something that circulates nor- 

 mally in the blood, the so-called " complement " of Ehr- 

 lich and Morgenroth. Under these circumstances the 

 " receptor " is conceived to be provided with two " hap- 

 tophore " groups, and becomes an " amboceptor," there- 

 fore, the one haptophore of which takes up and fixes 

 the invading bacteria, tissue-cell, or albumin molecule, 

 while the other pairs with the corresponding hap- 

 tophore of the complement, fixing the latter in close 

 proximity to the invading body, and thereby favoring 



