404 DAVID H. TENNENT 
These facts represent a definite advance in our ideas concerning 
the relation of chromosomes to somatic characters. They do not 
however aid us in deciding the question as to whether the nucleus 
is the sole bearer of the determinants of one character or the other. 
Godlewski (11), in his expression that neither the nucleus alone, 
nor the protoplasm alone, but both parts of the cell body are 
concerned, in the determination of hereditary characters, and that 
for the development of the paternal characters an interaction be- 
tween paternal nucleus and protoplasm is indispensable, raises 
an old objection in a new form and one which it is exceedingly diffi- 
cult to deny. As our knowledge of the interaction of nucleus and 
cytoplasm increases, particularly along the lines of nuclear syn- 
thesis, we have convincing evidence that the chromatin requires 
a very definite environment in order that it may increase. Conk- 
lin’s (712) observations on the fate of chromosomes centrifuged 
into the yolk in Crepidula is one ease in point. It is evident that 
Godlewski’s position is correct in so far as concerns the persistence 
and growth of the paternal nuclear material, and this material 
must persist and increase if it is to influence development. How 
much farther than that we may go in insisting on the necessity of 
all parts of the paternal germ cell body is somewhat doubtful. 
February 14, 1912. 
