SOMATOGENESIS 253 



(Conklin). Neither of these two conceptions is in ac- 

 cordance with the facts as known to-day. 



3. WHAT is SOMATOGENESIS? 



Development is not simply the unfolding or assort- 

 ment of what is already present in the germ nor is it 

 the miraculous writing of something new upon a clean 

 slate. Rather it is the orderly initiation and sequence 

 of new structures and functions conditioned by the 

 interaction of the germinal elements present in the egg 

 or ovule. 



Thus somatogenesis is the study of the emergence of 

 bodily structure out of hereditary sources. Like the 

 evolution of species, which has so enthralled the minds 

 of thinking men, somatogenesis in a parallel way is the 

 evolution of the individual. No doubt each of these 

 epic histories will eventually furnish the key and vo- 

 cabulary to the other. 



Both somatogenesis and garnet ogenesis, which con- 

 cerns the origin of the germ-cells themselves, are cyto- 

 logical in their terminology, and are referable to the 

 germplasm (see Figure 78), as contrasted with the 

 Mendelian and biometric aspects of genetics which are 

 not primarily cytological but are, on the contrary, 

 statistical in method, dealing directly with somato- 

 plasms. 



4. THE FACTORS IN SOMATOGENESIS 



Somatogenesis deals with the interaction of at least 

 two sets of factors, viz., (1) hereditary, and (2) en- 

 vironmental. 



