134 W. R. B. ROBERTSON 
of the small chromosome tetrads in the first spermatocyte cells 
of Schistocerca in his paper (March 713) on “ Variations in the 
size of chromosomes.’’ His paper deals chiefly with variations in 
size of chromosomes due to, what he believes to be, their unequal 
growth in the cell. Thinking that the whole paper was devoted 
to ‘variation due to unequal growth,’ I overlooked the latter part 
in which he illustrates and describes briefly a few cases of what he 
considers unequal division in the first spermatocyte. One of 
these cases (his fig. 86) may possibly be due to faulty conditions 
of sectioning. The other cases (his figs. 88, 85 and 87 to 91) 
are probably variations similar to those Carothers has since 
described in Brachystola, Arphia, ete. That ‘‘size variations 
may be due to unequal growth” I am inclined to doubt, but 
Hartman is to be given credit for recognizing the importance of 
variation in chromosome size in its relation to ‘variation’ in 
‘animals,’ since his work was done while teaching in a high school 
away from any university contact and especially since he was 
entirely ignorant of the Mendelian laws and their relation to 
variation. Had he known of these and the related work, he 
would likely have come to the same conclusions that I have. 
