664 



THE AMERICAN NATURALIST [Vol. LIII 



tlie prc-Meiulelian conception that sometliin- new is produce.l by 

 the act of hybridization. 



In his tliird hypothesis, tlie most eharaeteristie and the most 

 involved of this frroup, there seems to be some confusion in the 







fis to whether the environment has 



produced its 



effect directly 



upon the grametes, or through its 





of the rate of 



ont()<rei]y. The latter, however, is 



clearly implie 



d in several pla( 



ses. But, beyond speaking of hypo- 

 ytoplasmic! determiners," he makes 



no attempt to 



1 even postulate 



a mechanism by which the rate of 







^^. on tlu' (^videnVe, a somatic modi- 



fication, directly dependent ( 



,n temperature and moisture— can 







(M-ni-i)hisin. In regard to the direct 



effects (immediate or cuimili 









rlie author makes unich throughout 



