1913] CURRENT LITERATURE 405 
factors for yellow endosperm, Y; and Y;2, of which one is much more effective 
in producing the yellow pigment than the other. Such an assumption he 
regards as “‘violent,’’ it being just as violent as have been the assumptions of 
all Mendelian experimentalists who have made mathematical interpretations 
of breeding facts. The author is also greatly disturbed over the question of 
whether or not the segregation ratios that he obtained fit the theory of error. 
It seems to the reviewer, however, that considering the possibility of experi- 
h only 
variations of classification due to the difficulty of Totacabitos light yellows - 
from white, the author concludes “that while the segregation is usually numeri- 
cally exact, it is by no means complete; that is, the dominant character is not 
completely. absent from individuals of the recessive class.” ‘‘ This,” he says, 
“is shown not only by the presence of a faint yellow color in most of the seeds, 
but also by the fact that apparently pure white seeds from an ear in which the 
classes were well marked may produce seed with a fully developed yellow 
color when self-pollinated.”” Consequently he favors the idea of gametic 
impurity in the sense that extracted dominants and recessives may transmit 
traces of the alternative character. 
Again this conclusion seems opposed to the facts submitted. If one has a 
mother seeds proved to be 3:1; this the author either has not done or has not 
ry sche ms then the me ? ears obtsined . not again breed true, one might 
; but the author reports no such 
evidence. ‘Ba a matter of fact, extracted recessives and extracted dominants 
do appear to throw the alternative character on rare occasions, but the phe- 
nomenon is so rare that one may better assume that a germinal rearrangement 
(mutation) has occurred. Of course in any species some variations are more 
likely to occur than others, which may be taken as evidence of a kind of 
latency. But this is only the kind of latency that is analogous to the tendency 
of a chlorine atom to split off from a complex benzene derivative, rather than 
one of the more conservative radicals such as methyl. It is evidence that 
certain rearrangements in a particular germ plasm are more likely to occur 
than others.—E. M. East 
Studies of Nicotiana hybrids.—In two papers, appearing almost simul- 
taneously, GoopspPEED® has reported the results of his investigations on 
Goopsprep, T. H., Quantitative studies of inheritance in Nicotiana hybrids. 
Univ. Calif. Publ. 5: no. 2. pp. 87-168. pls. 29-34. 1912; ibid. no. 3. pp. 169-188. 
1913. 
