GAGER: CRYPTOMERIC INHERITANCE IN ONAGRA 469 
Lillie* has recently held that all hypotheses involving the exist- 
ence of determinants or character units have served their time, 
and, referring to the work of Guyer and Montgomery, has em- 
phasized the fact that germ-cell elements (chromosomes) may be 
segregated in nuclear and cell division. This, of course, is well 
known, and experiments on the effects of radium rays on nuclear 
division have shown that normal segregation may be greatly 
altered, and that even elimination of chromatin may be arti- 
ficially induced in this way.* 
‘I conceive it as quite probable that in the primordium of the 
epicotyl of the double primrose-plant such a segregation of chro- 
matin material (possibly not entire chromosomes) occurred, ac- 
companying or inducing the organization of two growing points, 
each the primordium of an epicotyl, and possessing an unlike 
relation between the hereditary elements of the cells. N ot, neces- 
sarily, an unlike hereditary composition, for the characters un- 
folded in the F; and F; generations showed clearly enough that the 
characters of an organism that actually appear are a function— 
not alone of the inheritance of the cells, but of a relation that 
obtains between various inheritances, some being dominant, others 
recessive. The work of de Vries has clearly demonstrated that 
“hereditary potentialities’’ which exclude each other in the active 
state, may occur together when one or both are latent. 
A qualitatively different chromatin content in the cells of the 
two growing points may have been the cause of the development 
of certain enzymes normally absent, or the repression of other 
ferments ordinarily present. Or these chromatin differences may 
have given some ferment a suitable body to act on in the one case 
and not in the other. Since such things as enzymes and ferment- 
able substances are known to exist in plant cells it does indeed 
seem unnecessary to call in the assistance of an imaginary, new 
kind of body, until the ones already actually experienced have 
been shown to be inadequate. 
Certain it is, however, as the rich mass of illustrations brought 
together by Darwin and by de Vries has previously emphasized, 
that the inheritance of a character and its expression are two 
entirely different things. The appearance of the double Onagra, 
* Gager®, Chapt. XVII. 
