432 



GERMINAL ORGANIZATION 



INDUCTION PHENOMENA 



five or six years in focussing on proteins and nucleoproteins as the most likely 

 answers to this enigma. 



Without really attempting a classification of the methods used, let us begin 

 with the techniques which have succeeded in isolating a fraction endowed with 

 some definite inductive effect, and continue with those which, moreover, apa- 

 parently bear on known biochemical entities. 



For practical reasons, much work has been done with guinea-pig liver and 

 kidney, which, as we have seen, possess rather opposite inductive properties. 



Fig. 86. Influence of host region on the nature of xeno-inductions. As abscissae, the four 

 main regions: I, acromerit; II, deutomerit; III, cormomerit; IV, ouromerit {cf. Fig. 39). 

 A. the distribution of brain parts; B. sensory organs. C. structures of the tritomerit. From 



Vahs, 1956. 



