164 HAEMOLYSIS BORDET'S VIEWS 



body and then with complement, some of the immune body, but 

 none of the complement, might be dissociated from the combina- 

 tion, and become free in the fluid. It is difficult, though perhaps 

 not quite impossible, to reconcile this experiment with Ehrlich's 

 theory, whilst it is really explicable on that of Bordet ; but Muir 

 (whose recent work on this difficult point should be consulted) 

 has not come to a definite conclusion as to the nature of the 

 combination. 



Bordet also holds peculiar views on the subject of the union 

 of corpuscles and immune body. According to Ehrlich, the com- 

 bination is due to a strong chemical combining affinity between 

 the two substances, and the resulting compound is a stable one, 

 which is not readily dissociable. Cells thus activated possess a 

 strong affinity for complement, and the whole process is a chemi- 

 cal one, dependent on ordinary chemical laws and obeying the 

 laws of multiple proportions. This was, on the whole, confirmed 

 by Muir, who proved that corpuscles combined with multiple 

 doses of immune body took up multiple doses of complement ; 

 but he also showed that the corpuscle-antibody compound did 

 dissociate, so that when corpuscles which had been saturated 

 with immune body were placed in contact with normal corpuscles, 

 some of the amboceptor left the sensitized and attached them- 

 selves to the normal. Bordet adduced evidence to show that the 

 combination is of a remarkable nature, and dependent on obscure 

 chemico-physical reactions. He took a sample of haemolytic 

 serum, and determined the amount of blood which it could 

 haemolyze when the two were mixed together. We may assume, 

 on Ehrlich's theory, that all the suitable receptors in the cor- 

 puscles were saturated with amboceptor. But Bordet showed 

 that if the corpuscles were added a little at a time, a very much 

 smaller dose might take up all the immune body. Hence he 

 compared the process to the staining of filter-paper when im- 

 mersed in a dye. If the paper be added at once, it will be stained 

 a uniform colour, whereas if it be added a little at a time, the first 

 pieces will be stained deeply, the subsequent ones less and less, 

 until the dye is completely absorbed. It would appear to explain 

 the phenomenon equally well if we assumed that the corpuscles 

 could be haemolyzed by fewer amboceptors than they could take 

 up, and there is some experimental evidence of this. Thus Muir 

 showed that after red corpuscles have been dissolved by haemo- 

 lytic sera, the addition of more immune body will lead to the 



