230 A. B. MACALLUM. 
the spermatozoid, but what is held in the cytoplasm of the 
ovum apparently is retained by the latter. 
These observations on the diffusion of the iron-holding sub- 
stance from the “ nucleus” of the spermatozoid into its cyto- 
plasm coincide with those of van Beneden upon the changes 
which take place in the spermatozoid of Ascaris megalo- 
cephala after it penetrates the ovum. He found that the 
protoplasm of the free spermatozoids' manifests no affinity 
for staining compounds, while its capacity for absorbing and 
retaining all colouring matters becomes remarkable immedi- 
ately after it enters the ovum. As the “nucleus” at the 
same time loses in part its affinity for stains, he came to the 
conclusion that a part of the chromatic substance (chromatin) 
of the “ nucleus’’ becomes dissolved in the cellular substance 
(cytoplasm). O. Zacharias” has also pointed out that the proto- 
plasm of the free spermatozoid, apart from its “ nucleus,” is 
absolutely unstainable, but after it penetrates the ovum it at 
once manifests an affinity for colouring matters. Kultschitzky,3 
referring to the reactions with staining fluids, suggests that 
possibly the “nucleus” gives off to the cytoplasm of the 
spermatozoid a portion of its chromatin, or that, in other 
words, not all of the chromatin of the ‘‘ nucleus” is employed 
in the construction of the male pronucleus. I have found in 
my preparations that the cytoplasm and “ membrane ” of the 
spermatozoid which has penetrated the ovum, and, frequently 
also, that portion of the cytoplasm of the ovum in the im- 
mediate vicinity of the spermatozoid, have a slightly greater 
affinity for colouring matters than the cytoplasm of the free 
spermatozoid or of the unimpregnated ovum. 
In many of his illustrations van Beneden represents that 
part of the spermatozoid which I have called the “membrane ” 
1 © Recherches sur a maturation de |’ceuf et la fécondation,” ‘ Archives de 
Biologie,’ vol. iv, p. 265, 1883. 
2 “Neue Untersuchungen iiber die Copulation der Geschlechtsprodukte 
und den Befruchtungsvorginge bei Ascaris megalocephala,” ‘Arch, 
fir Mikr, Anat.,’ vol. xxx, p. 111, 1887. 
3 “Die Befruchtungsvorginge bei Ascaris megalocephala,” ‘Arch. 
fiir Mikr, Anat.,’ vol, xxxi, p. 567, 1888, 
