i6o 



H.EMOLYSIS ANTI AMBOCEPTOR 



and Ehrlich compares it to a process of physical absorption. The 

 presence of the phenomenon must be borne in mind, since it must 

 make us careful how we interpret the mere disappearance of 

 complement from a fluid after it has acted on articulate sub- 

 stances. The true test of specificity is its action on these 

 substances, not its absorption by them. The yeast cells are in no 

 ways injured through having absorbed complement. 



We have not yet finished our study of the complements, but it 

 will be convenient to continue it later, and to conclude here Ehrlich's 

 studies on the antilysins. Anticomplement has been already 

 discussed, and we will now turn to anti-amboceptor. 



This is a substance of nature different to any that we have 

 previously studied, in that it is an antibody to an antibody. It is 

 prepared by injecting an immune serum into an animal other than 

 that from which it was derived. Thus, if an antityphoid (bacterio- 

 lytic) serum procured by immunizing a horse with typhoid bacilli 

 be injected into a rabbit, the serum of the latter acquires the 

 power of neutralizing the bacteriolytic action of the former. 

 Antibodies to antibodies cannot always be produced ; thus, anti- 

 antitoxin is not yet known. Again, Metchnikoff was unable to 

 prepare antispermotoxin by injecting a cytolytic serum for sperma- 

 tozoa into the guinea-pig. In this case there can be no question of 

 the absence of suitable receptors, for the animal's spermatozoa are 

 attacked in vitro by the serum injected. Hence Ehrlich made 

 the assumption of the presence of sessile receptors, which are not 

 cast off when the suitable antibody is injected. 



In studying the anti-amboceptor concerned in haemolysis, 

 Ehrlich first prepared a haemolytic serum by injecting a rabbit 

 with ox blood. When the serum of the latter was found to be 

 powerfully haemolytic, it was injected subcutaneously into a goat : 

 1 20 c.c. was given during an interval of two months. At the end 

 of this time this goat serum was powerfully antihaemolytic. This 

 was shown as follows : 0-00125 c.c. of (immune) rabbit serum was 

 found to haemolyze completely i c.c. of a 5 per cent, emulsion of 

 ox corpuscles, provided that sufficient normal guinea-pig serum 

 is added to provide complement. Now three times this amount 

 (0*00375), pl us '5 f t ne S oa t serum, was added to i c.c. of the 

 emulsion of corpuscles, allowed to act at 40 C. for an hour, centri- 

 fugalized, and 0-15 c.c. of normal guinea-pig serum (complement) 

 added to the corpuscular sediment. No solution took place, so 

 that 0-5 c.c. of the anti-antiserum had completely neutralized three 



