1392,] Embryology. 625 
As I have already indicated in my previous note on the Sertoli’s 
cell, the cyanophilous quality of the spermatozoon nucleus is only the 
final phase of the varied series of color-reactions, which the sperm-pro- 
ducing cell presents at different stages of its development. The male 
germinal substance is not always blue in its color reaction. The male 
germinal substance at the beginning (spermatogonium stage), is not 
eyanophilous, but its color reaction is violet, due probably to a mix- 
ture of blue and red color; while at the next stage (spermatocyte), the 
color reaction of the chromosome is decidedly green, with one or two 
intensely erythrophilous nucleoli. 
The transition of the chromatophilous qualities of the nuclear 
substance of the male cell from violet (spermatogonium), green 
(spermatocyte), greenish-blue (spermatide) and deep blue (sper- 
matozoon), each new color-reaction corresponding to the mor- 
phological change in the sperm-cell, is certainly very instruc- 
tive as clearly shown in my preparations illustrating mammalian 
spermatogenesis. The change in the chromatophilous quality of the 
male cell at different stages of its existence, may be due to corre- 
sponding changes in the quality of the protoplasm itself, and the 
whole phenomena of the successive series of forms of the sperm-cell 
must be due to the corresponding alteration in the nature of the proto- 
plasmic material: when the male cell assumes its final stage as a well- 
developed spermatozoon, with its complicated apparatus for locomo- 
tion, accompanied, as in many cases, with an accessory apparatus, 
which facilitates the penetration of the sperm-nucleus into the substance 
of the ovum (as the head-spine for boring and the recurved hook at its 
tip, etc.), the quality of the protoplasmic substance has changed so 
much as to take an entirely different color from that of the ovum, 
which maintains the typical characteristics of an animal cel]. That 
the ovum and the sperm become differently colored is, then, just what 
we might expect on a priori grounds, knowing the analogous differ- 
ences mentioned in the history of the spermatozoon alone. 
The critical point one is most interested to know is, whether the 
blue color, which characterized the nucleus of the spermatozoon, still 
persists or not, after the sperm-cell has entered into the substance of 
the ovum, and the form of its nucleus has undergone change by 
becoming spherical again. According to Auerbach’s theory of hered- 
ity, the blue color must persist. Iam not able to say anything defi- 
nitely on this point, for I have not yet finished my research on this 
particular subject. I have said enough, however, to show, that the 
1This Journal for May, 1892, p. 442. 
