ANTIGENS, HAPTENS, ANTIBODIES, ETC. 433 



It has l)et?n sliuwji tJiat t37)]ioi(l H -aggiutiniiis in lioi'se 

 antisera can be concentrated by treatment with nin- 

 hydrin and precipitation by acid or salts. The O- 

 agglutinins of typhoid and the Type I pneiimococcus 

 agglutinins in horse antisera are partially destroyed by 

 ninhydrin. In rabbit antisera the apparent tit re of 

 typhoid H -agglutinins is increased 2 to fourfold by the 

 action of ninhydrin, whilst the typhoid -agglutinins 

 and pneumococcus antibodies are not affected, unless the 

 treatment is prolonged. 



Complement 



In the various lytic reactions, bacteriolysis and 

 haemolysis, for example, it has been established that two 

 serum factors are involved — (1) the comparatively heat 

 stable immune body which is increased in amount during 

 immunisation and (2) the very labile complement, or 

 alexin, which is present in normal as well as in immune 

 sera and which is not increased in amount during 

 immunisation. 



In the case of haemolysis, Ehrlich considered that the 

 immune body, haemolysin or amboceptor, had two 

 affinities, one for the cell and the other for the haptophore 

 or combining group of the complement. The complem' :it 

 then acted on the cell causing lysis in virtue of its active 

 or ergophore group, as Ehrlich called it. Bordet regarded 

 the immune body as a sensitiser with which the cell formed 

 a complex which had an affinity for complement and 

 adsorbed it ; the immune body itself has no visible effect 

 on the cells ; it is the complem^ent which brings about 

 the lysis . It has been considered that in the lysis of cells 

 the complement acts as a proteoljrtic enzyme, but it 

 difff^rs in one respect at least ; its effects are governed by 

 the Law of Mass Action, that is, it appears not to act as a 

 catalyst. Moreover, the cell walls of red blood corpuscles, 

 for example, are not destroyed nor is the liberated haemo- 

 globin attacked, which appears to be in contradiction to 



