128 
Thos. H. Montgomery, jr. 
II. General Results from the Preceding. 
The observations just presented allow these main conclusions: 
1. In follicles 1 and 3 of the testis of EimMstus sp. the spermato- 
cytes, spennatids and spermatozoa are constantly much larger than in 
follicles 4, 5 and 6, wliile in follicle 2 they are constantly somewhat smaUer. 
2. This is a voluininal difference, apparcntly not associated with 
diniorphism of the spermatozoa, dne to constant differences in volume 
in the several follicles of niass of karyolymph, linin (substance of mantle 
fibres), cytoplasm, and mitochondiial substance. 
3. The chromosomes, however, are constant in their behaviorinallthe 
follicles with regard to number, mass, mode of conjugation and ofdivision. 
4. The dimegaly of the spermatocytes arises in the early growth 
period, and is due directly to differences of the nurse cells of the different 
follicles, i. e. to degree of nutrition. 
These results lead to the following ones of greater Import: 
5. The growth of germ cells may be modified by them trophic en- 
vironnient, and dimegaly of spermatozoa may be produced other\\ise than 
thi’ough intrinsic differences. Om’ observations would show that these 
germ cells become as much modified by amount of nutrition received as 
do somatic cells. 
6. It is possible that the amound of those substances, cytoplasm, 
karyolymph, linin, mitochondria, which vary according to the size of 
the spermatozoa, may be of use in determining the relative value of 
the sperm in fertilization, consequently sex. With the head of sperm is 
introduced into the egg all of these substances, and it is possible that in 
a considerable number if not all cases the whole Spermatozoon may enter 
the egg ; that is certainly the case with the sperm of Ascaris. The obser- 
vations showing that the sperm flagellum is left outside of the egg are 
few in number, and much more evidence is necessai-y before we can put 
it dovTi as a rule that only the head and middle piece enter. But with 
the Penetration of head and middle piece much more than chromatin 
is inti’oduced, consequently the chromosomes alone need not determine 
the sex. This is put forth simply as a Suggestion to be tested. 
7. The relative constancy of chromatin mass in spermatocytes and 
spennatids of very different volumes speaks strongly for its enzyme 
nature. Eitschistus presents a very beautiful and decisive natural experi- 
ment in which cells of the same kind receive different degrees of nutri- 
tion, and in which des])ite marked growth differences of other substances 
the mass of chromatin remains very constant. Further, while a spermato- 
