366 BIOLOGY: GENERAL AND MEDICAL 



found to contain the third element required, which is 

 known as the complement. This complementary sub- 

 stance is, therefore, something normal to the blood, 

 whose presence does not depend upon any experimental 

 manipulation and is not capable of effecting any change 

 in the blood corpuscles by itself. It is, however, acti- 

 vated by the amboceptor. If the process of hemolysis 

 by complement and amboceptor is to be thoroughly 

 understood, it may be well to visualize it in a manner 

 shown in the following diagram : 



ci. a. c. 



FIG. 132. Diagram illustrating the factors concerned in hemolysis, cytolysis, 

 and bacteriolysis, cl, The cell to be dissolved; c, the complement or solvent by 

 which it is to be dissolved; a, the amboceptor or intermediate body by which 

 the two can be brought together. 



It is now apparent why the amboceptor is so called, 

 for it is shown to take hold of the complement on one 

 hand and of the corpuscle on the other. It will become 

 clear why the complement, or solvent, an enzymic sub- 

 stance, is unable to accomplish anything by itself, not 

 being able to connect with the corpuscle, and why the 

 amboceptor not having solvent properties in itself, can 

 do nothing, though it may connect with the corpuscles. 



Great interest attaches to the source of the antibodies. 

 Undoubtedly they are of histogenetic and of cellular 

 derivation. It was originally insisted that they were 

 derived from those cells for which the antigen had some 

 specific affinity, but this view has gradually given place 

 to the opinion that many cells participate in their forma- 

 tion. 



A theory of antibody formation known as the lateral 

 chain theory, suggested by Paul Ehrlich, has been ex~ 



