10 IMMUNE SERA 



the side chains or receptors which are given off by 

 the cells and thrust into the circulation. The way 

 in which these side chains or receptors are thrust 

 off as a result of the immunizing process, Ehrlich 

 explains by means of Weigert 1 s Overproduction 

 Theory. 



At the meeting of German Naturalists and 

 Physicians held at Frankfurt in 1896, Weigert * in 

 discussing regeneration, advanced an hypothesis the 

 essential features of which are that physiological 

 structure and function depend upon the equilibrium 

 of the tissues maintained by virtue of mutual 

 restraint between their component cells ; that destruc- 

 tion of a single integer or group of integers of a 

 tissue or a cell removes a corresponding amount of 

 restraint at the point injured, and therefore destroys 

 equilibrium and permits of the abnormal exhibi- 

 tion of bioplastic energies on the part of the remain- 

 ing uninjured components, which activity may be 

 viewed as a compensating hyperplasia; that hyper- 

 plasia is not, therefore, the direct result of external 

 irritation, and cannot be, since the action of the 

 irritant is destructive and is confined to the cells 

 or integers of cells that it destroys, but occurs 

 rather indirectly as a function of the surrounding 

 uninjured tissues that have been excited to bio- 

 plastic activity through the removal of the restraint 



1 Weigert, Verhandlungen der Ges. deutscher Naturforscher 

 iind Aerzte, 1896 



