188 WARFARE IN THE HUMAN BODY 



operations in the adult organism. To say that it contains 

 germ-plasm is to assume something without real proof, 

 and no observations of germ-tracks, or theories of 

 germinal epithelium as ultimate facts, can invalidate 

 the conclusion that, as the function and form of the 

 adult are determined by definite agents, so the functions 

 and form of the free oocyte, sperm cell, or zygote, are 

 thus determined from moment to moment of its develop- 

 ment. Such a view takes into account the law of 

 parsimony, which requires us to posit no unknown 

 factors where known ones can be seen producing similar 

 results. 



Pure early theoretic Weismannism has no doubt been 

 modified and diluted. So has early theology. We are 

 no longer required to assent to a cloud of biophors, a 

 hierarchy of determinants, and a whole angelology of ids 

 as a sine qua non to biological salvation, though it may 

 possibly be shown that the dilution of the theory has not 

 allowed for the truth in it, if it is considered rather as an 

 illustration than as true theory. But still sufficient of the 

 suggested machinery remains to enable the neo-Darwinian 

 to believe that all change is due to minute germinal varia- 

 tions in the chromosomes, though no one of them has yet 

 acknowledged that such variations are variations in definite 

 tools, as even Weismann himself might have acknowledged 

 if as much had been known of the endocrines in his time 

 as is known now. Disguise it as they may, the whole theory 

 as held is concealed vitalism and a circulus in definiendo. 

 If the germ-plasm is an ultimate fact not resolvable into 

 recognizable scientific factors it is absurd to call the theory 

 scientific, unless it is asserted that " nature " and " life " 

 are scientific words instead of verbal shorthand. Nothing, 

 indeed, can be described as scientific explanation which 



