The Cytoplasm as Specific Substrate 205 



conflicting. But some or all of the following possibilities may be 

 involved: (1) a selection of already present rare mutants controlling 

 the specific enzyme; (2) a "steady state" condition, as discussed 

 before, allowing the genie material to produce one or another product 

 according to the environment; (3) this condition may be self -perpetu- 

 ating even in the absence of the genie material (after segregation) or 

 may not; (4) the condition may be reversible by exhaustion of 

 particles or by inverse environmental action; (5) mutation may play 

 a role in different ways; (6) induced mutation of plasmagenes may 

 take place (my own opposition to such a view has been registered). 

 Dauermodifikation and enzymatic adaptation will probably be found 

 to have the same background; but, since neither is yet understood 

 completely, it is impossible to explain one in terms of the other. This 

 is a frontier which must be watched. 



C. PLASMON ACTION OF THE SPECIFIC SUBSTRATE TYPE 



If we call (see II 2 D) a specific action of the cytoplasm as a 

 whole a plasmon-type action, we may distinguish two major categories: 

 (1) a specific physicochemical structure or biochemical nature of the 

 cytoplasm affecting genically controlled processes in the nature of a 

 specific substratum which remains constant within a genetic line; (2) 

 a specific constitution of the entire cytoplasm which alone controls 

 specific features of structure or function, and might therefore be con- 

 sidered a genuine cytoplasmic inheritance. 



a. Mendelian segregation in different cytoplasm 



The first type of plasmon action would be recognized when an 

 ordinary Mendehan character changes its phenotype in the presence 

 of cytoplasm of different origin. Experimentally this would involve 

 phenotypical difference of reciprocal crosses and constancy of these 

 differences in the maternal lines of following generations. A large 

 number of experiments demonstrating this situation was performed 

 with the gypsy moth Lymantria dispar ( Goldschmidt, 1924). A series 

 of geographic races exist with, among others, differences in the 

 markings of the caterpillars. Some races show a bright pattern of light 

 spots of epidermal origin which remains through all instars. In other 

 races this pattern is present but less extended, and these quantitatively 

 different patterns are based upon multiple alleles with additional 

 control of multiple modifiers. In addition to this basic pattern, a 

 simple Mendelian factor in some races produces a cuticular dark 

 pigment which overlays the bright pattern and covers it more or less 



