34 MODES OF RESEARCH IN GENETICS 



well await the results of further inquiry." Minot^ 

 expressed essentially the same conclusion in one 

 of his Jena lectures. Doncaster ^ after reviewing 

 the matter says that the evidence, *' while not 

 proving that the chromosomes are directly con- 

 cerned in the transmission of inherited characters, 

 makes such a hypothesis very plausible. Much 

 unnecessary confusion, however, has arisen, from 

 stating the hypothesis in the form — 'the chromo- 

 somes are probably the bearers of inherited 

 characters.' Evidence has been adduced that 

 the cytoplasm plays some part in determining 

 these characters, and it has therefore been main- 

 tained that the statement is disproved. No one, 

 however, would suppose that the chromosomes 

 could act alone; they must act in and by their 

 relation with the cytoplasm, and if the cytoplasm 

 is that of a different species, the total ejffect must 

 necessarily be different." 



To summarize this section of the paper, it may 

 be said that while cytology attacks directly one 

 of the basic elements of the problems of heredity, 

 gametogenesis, it finds immediate and serious 

 limitations in two facts. The first is that the 

 method of research in cytology is the morphologi- 



iMinot, Charles S. "Modern Problems of Biology," Philadel- 

 phia, pp. 1-123, 1913. 



2 Doncaster, L. "Chromosomes, Heredity and Sex: A Review 

 of the Present State of the Evidence with Regard to the Material 

 Basis of Hereditary Transmission and Sex-Determination." Q. J. 

 Micr. Scl, Vol. 59, pp. 487-521, 1914. 



