278 BACTERIOLOGY 



wanting an explanation of the mechanism through which 

 these interesting phenomena were accompHshed. 



Omitting a group of highly suggestive observations made 

 by many competent investigators, we encounter the most 

 elaborate and at the same time the most fascinating effort 

 to interpret the nature of the reactions occurring in the 

 induction of immunity as well as those fundamentally 

 accountable for the natural condition. 



To the genius of Ehrlich' we owe the "side chain" or 

 "lateral band" theory (Seitenkettentheorie) of immunity. 



Its fundamental features comprise the acceptance of 

 Weigert's doctrine concerning the mechanism of physiolog- 

 ical tissue-equilibrium and repair; and the assumption of a 

 specific combining relation, or affinity, between toxic sub- 

 stances and the cells of particular tissues. 



At the meeting of German Naturalists and Physicians 

 held at Frankfort-on-the-Main, in 1896, Weigert^ 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 its component cells; that destruction 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 energies, on the part 

 of the remaining uninjured components, which activity may 

 be viewed as a compensating hyperplasia; that hyperplasia 

 is not therefore the direct result of external irritation, and 

 cannot be, since the action of the irritant is destructive and 



1 Klinisches Jahrbuch, 1897, Bd. vi, Heft 2, S. 300. 



2 Neue Fragestellungen in der pathologischen Anatomie, Verhandlungen 

 der Ges. deutscher Naturforscher und Aerzte, 1896, S. 121. 



