A Study of Chromosomes and Chromatin Nucleoli 
in Euschistus crassus. 
By 
Katharine Foot and E. C. Stroheil. 
With plates II — IV. 
When an atterapt is made to formulate hypotheses from given facts 
such hypotheses are challenged by any variations in the facts that are 
inconsistent with the theories, and these variations demand at least a 
plausible explanation. Merely an autocratic denial of such variations or 
setting them aside as pathological or due to faulty technique is not enough 
to satisfy the unprejudiced observer. 
The fact that students of the structures of the cell hold such dia- 
metrically opposed views as to their possible fundamental significance 
and that facts in evidence of these opposing views can be demonstrated 
in the same material would seem to be proof of great variability shown 
by the structures theniselves as well as a great diversity in the point of 
view from which they are attacked. This is true of the chromosomes 
which have given rise to as much controversy as many a theological 
tenet having at one extreme their orthodox adherents who have faith 
in theh’ causal nature and at the other extreme the skeptic who believes 
they are simply the expression, not the cause of cell activities. The 
latter gives full value to all structural variations which it woiüd seem 
ought not to exist if the Claims for the causal nature of the chromosomes 
are vaüd; such facts as a difference in the number of chromosomes in 
closely aUied species — differences in the behavior of the chromosomes 
in closely allied species — inconstancy in the number of chromosomes 
even in the same individual of a given species — inconstancy in the 
form of the chromosomes in the same individual — inconstancy in the 
relative size of the chromosomes in the same individual and inconstancy 
