INFECTION AND IMMUNITY. 569 



At the meeting of German Naturalists and Physicians 

 held at Frankfort-on-the-Main, in 1896, Weigert 1 ad- 

 vanced 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 its component cells ; that de- 

 struction 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 exhibition of bioplastic ener- 

 gies on the part of the remaining uninjured components, 

 which activity may be viewed as a compensating hyper- 

 plasia ; that hyperplasia 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 unin- 

 jured tissues that have been excited to bioplastic activity 

 through the removal of the restraint hitherto exerted by 

 the cells destroyed by the irritant ; and, finally, when 

 such bioplastic activity is called into play there is always 

 %percompensation /. e., there is more plastic material 

 generated than is necessary to compensate for the loss. 

 Ehrlich applies this idea to the individual cell, which 

 he conceives to be a complex molecule, comprising a 

 primary central nucleus to which are attached by side 

 chains its secondary atom-groups, in much the same way 

 that our conception of the reaction-structure of complex 

 organic chemical compounds is represented graphically. 

 Injury to one or more of these physiologically essential 



L Weigert, Carl : " Neue Fragestellungen in der pathologischen Anat- 

 omic," Verhandlnngen der Ges. deutscher Naturforscher und Aerzte, 

 1896, S, 121. 



