further Examination of tin' Cell-Theory 



appear in regular succession till the adult stage with its 

 distinctive characters were reached. The great point to be 

 emphasized is that if we are guided strictly by the observa- 

 tional and rational methods by which all our knowledge of 

 organic development has been built up, we see that the ef- 

 fort to conceive germ-cell promorphology or prophysiology 

 in terms of representative units succeeds only in so far as 

 we deceive ourselves into believing that we know what we 

 do not know, and probably never can know, about the struc- 

 ture and functions of the genn, and by thus deceiving our- 

 selves, believe ourselves relieved of the necessity of endeavor- 

 ing to learn what the actual structure and function of the 

 gcrni is. 



The metaphysical promorphology and prophysiology of 

 the germ which, culminating in the "determinants" of Weis- 

 inann, have befuddled the thinking of many biologists, hold 

 exactly the same place in the logic of biology that phlogis- 

 ton held for well nigh a century in the logic of chemistry. 

 There is surely something in the wood that is a cause of 



* flame, so why not say the characters of the flame are 

 rried" in the wood by units capable of doing that sort 

 thing? And how easy and complete the explanation of 

 flame would be on that basis ! For minds of such cast as 

 t of .lost ph Priestley (about the last ardent defender of 

 ogiston) and as those of Weismann and his disciples, 

 lanations of this sort appear to have great fascination. 

 It is probably implied, if not definitely contended, by 

 e present-day geneticists, that the methods of analysis 

 employed by them, those, namely, of experimental breeding, 

 the application of Mendelian principles of inheritance, and 

 the correlation of these with chromosomal studies, are a 

 refutation of the conceptions above set forth. As a matter 

 of fact, though, the results of gcnctical analysis, so far as 

 thev are objective and not purely speculative, are entirely 

 confirmatory of the conceptions. 



