190 J. S. NICHOLAS 



a skip of one generation before the effect manifests itself. They have 

 interpreted this material as showing that the nucleus has a definite 

 effect upon the cytoplasmic relationship, and also that the cytoplasmic 

 forces cause a lag in the appearance of the nuclear constituents which 

 are responsible for the reversal of asymmetry in the second generation. 

 There is here an interesting link of reaction between cytoplasm and 

 nucleus, one which indicates that there is an interrelationship of rather 

 vital significance for the entire field of early organization. Lillie's ('29) 

 theory of the allocation of the various parts of the organism is well 

 known, a differentiation through segregation and differential dichot- 

 omy resulting in a definite localization of the different parts in a 

 rather quantitative way. Their qualities are quantitatively disseminated. 

 The analysis of the process of segregation shows that there is more 

 than a simple quality or quantity which has undergone localization in 

 the course of its movement to different regions. A tissue which may 

 become part of one definite organization in one region becomes part of 

 an entirely different set of organizations in another. The change in 

 positional setting is an important process in organization. 



An interesting and entirely convincing experiment in which genie 

 control is dominant over all other factors is shown in Robertson's ('42) 

 paper. By transplanting the ovary of the homozygous yellow mouse into 

 black agouti hosts a normal environment was provided for develop- 

 ment. The lethal factor, however, appeared in exactly the same way as 

 if the embryos were developing in a heterozygous yellow female. The 

 genie mechanism is clearly responsible for the lethal effect in the homo- 

 zygous yellow. Just what occurs in the blastocyst at the critical stage 

 at which the lethal characters become evident is not yet known. 



The Problem of Egg Constituents 



Surface changes in the egg are but an indicator of internal changes 

 which are magnified in the peripheral surface movements. The egg is 

 not a simple sphere with an outer limiting surface on which one who 

 runs may read, but it is a nebulous system in which there are multiple 

 reaction spheres delimited by the relations of movement within an 

 inner and an outer layer. 



If such could be held, then the primary arrangements within the egg 

 are due to differences in mobile capacity of the various substances 

 within a comparatively homogeneous system. The internal center is a 

 point of relative homogeneity from which forces emanate with a con- 



