132 THE LYSINS. 



only upon the corpuscles of the ox, but upon those of the goat as 

 well. If such a blood serum be treated with a sufficient amount of 

 the corpuscles of the ox, and the mixture separated in a centrifuge, 

 the supernatant fluid has no solvent action upon either ox or goat 

 corpuscles. In other words, the ox corpuscles have taken up all the 

 intermediary bodies in the blood serum. However, if this serum be 

 mixed with goat corpuscles and the mixture be separated in a cen- 

 trifuge, the supernatant fluid has no solvent action upon goat 

 corpuscles, but still possesses solvent action on ox corpuscles. This 

 experiment demonstrates that there are in the blood serum of a 

 rabbit immunized to ox blood at least two intermediary bodies, both 

 of which are capable of combining with ox corpuscles, while only 

 one combines with goat corpuscles. Intermediary bodies differ from 

 one another both in their cytophil and in their complementophil 

 groups. A given intermediary body will unite with a corpuscle 

 only when it finds in that corpuscle its appropriate receptor. And, 

 as has already been shown, the receptors in one and the same cor- 

 puscle, as, for instance, in the corpuscle of the ox, differ and take up 

 different intermediary bodies. In like manner, every intermediary 

 body will not combine with every complement; and combination 

 between an intermediary body and a complement can occur only 

 when their haptophorous groups are homologous. The existence of 

 two or more kinds of intermediary bodies in a given serum has been 

 also demonstrated by the formation of anti-intermediary bodies. If 

 a hemolytic serum be injected > in small quantities at intervals into 

 an animal there may be obtained from that animal a serum which 

 contains an anti-intermediary body, but its anti-action is not mani- 

 fest towards all intermediary bodies and may show itself only when 

 brought into contact with that intermediary body by means of which 

 the anti-hemolytic serum has been obtained, and it is in this sense 

 only that specific anti-intermediary bodies can be obtained. A 

 serum containing an anti-intermediary body prevents the action of a 

 hemolytic serum on the corpuscle in case that the action results from 

 its own specific intermediary body. The action of an anti-inter- 

 mediary body consists in preventing the union between the cytophil 

 group of its specific intermediary body and the receptor of the cell. 

 It is possible that intermediary bodies possessing different cytophil 

 groups may have the same complementophil group, or intermediary 

 bodies of like cytophil groups may have different complementophil 

 groups ; and it is still possible that there may be intermediary 

 bodies possessed of only one cytophil group and having two, three 

 or more complementophil groups. In his latest articles Ehrlich 

 designates the intermediary body as " amboceptor," indicating that 

 it has two haptophorous groups, but, as has just been stated, the 

 intermediary body may be a triceptor, quadriceptor, etc. 



Each complement has a haptophorous group by virtue of which it 



