416 TRANSMISSION 



species of highly developed organisms. Is this the " raw mate- 

 rial " out of which new species shall be evolved later on to take 

 the place of what is now so rapidly becoming extinct ? It is a 

 moving panorama, and we know neither the beginning nor the 

 end. It is all a part of a vast plan on which the universe is 

 founded by the Creator. We cannot doubt that the most com- 

 plex element of it all is life, nor can we doubt that the most 

 characteristic property of living matter is its progressive devel- 

 opment, bringing to light new activities and establishing new 

 relations with the world outside. Whether this property is wholly 

 internal and dynamic, or due, at least to some extent, to outside 

 influences, this is the chief mystery. 



SECTION IX VARIATIONS DUE TO CAUSES NOT AFFECT- 

 ING THE GERM ARE NOT TRANSMITTED 



This much is a logical conclusion. This much is fundamental 

 and axiomatic. The germinal matter is the only material that 

 passes over from generation to generation. The fertilized germ 

 is the only heritage, and it is the only avenue of transmission. 

 Whatever faculties or endowments the individual may possess, 

 he can transmit only those which can find lodgment and repre- 

 sentation in the germ, and whether the causes of germinal 

 changes are internal or external, or both, no variation can be 

 transmitted unless it affects the germ or unless the cause that 

 induced the variation also affected the germ. 



Variations due to causes internal to the body but external to 

 the germ are not transmitted. It is entirely possible that certain 

 variations, either of structure or of function, may arise from 

 irregularities in cell division during development due to local 

 rather than to germinal causes. For example, it has already 

 been noted that cells may at any time divide into unequal por- 

 tions, or into three instead of two parts, giving rise to abnormal 

 if not to pathological conditions. 



Almost all portions of the body are subject to those over- 

 growths called tumors, and while it is not yet definitely known 

 whether the causes of abnormal growth are external or internal 

 to the organism, they certainly are not located in the germ. 



