Resorption of the formed elements 93 



Another of Ehrlich and Morgenroth's experiments has furnished 

 the proof that the complement unaided does not fix itself to the red 

 corpuscles. A normal serum, unheated, which, by itself, is quite as 

 incapable of dissolving the red corpuscles as the fixative alone, is 

 mixed with some defibrinated blood. After the centrifugalisation of 

 this mixture, it is easy to demonstrate that the supernatant fluid 

 has lost none of its complement (alexine), whilst the red corpuscles 

 have fixed none. 



If, instead of an inactive serum, we take a serum which is capable 

 of dissolving the red corpuscles and which consequently contains the 

 two haemolysing substances, and if we place it in contact with the 

 corresponding red corpuscles, at a temperature between and 3 C C., 

 the solution will not take place (Ehrlich and Morgenroth). Under 

 these conditions the fixative certainly attaches itself to the red 

 corpuscles, but the alexine remains in solution, unused. It is only 

 necessary, however, to heat the mixture up to 30 C. to bring about 

 rapid haemolysis. 



From their very ingenious experiments, as a whole, Ehrlich and 

 Morgenroth conclude that the fixative possesses two different affini- 

 ties : one for the red corpuscle and another for 

 the complement. Of these two affinities the 

 stronger is that which links it to the red cor- 

 puscle, for this is manifested at a very low 

 temperature. In order that the fixative may 

 combine with the complement a much higher 

 temperature is requisite. Ehrlich comes to the 

 conclusion that the molecule of the fixative 

 possesses two haptophore groups, or groups Flo 19 schema of 

 capable of chemical combination. The first of Ehriich's theory. 

 these links it to a corresponding molecule of the c , complement (alexine, 

 red corpuscle to which he gives the name of cytase) am, ambo- 

 receptor ; the second combines the fixative with cep * or ( fixa * ive )-f' re - 



,. , .. . i . ,i . ceptor of the red cor- 



the molecule of the complement and in this way pus cie. 



introduces the latter into the red corpuscle. (After Levaditi in the 



These investigators give a diagram which greatly Presse mtdicaie.) 



facilitates the understanding of their hypothesis 



(Fig. 19). They seek to prove that the combinations of the fixative 



with the red blood corpuscle and with the complement follow the law 



of definite multiples and that these phenomena must, in consequence, [100] 



be looked upon as being of a purely chemical character. 



