34 The Significance of Sex. [ Jan. 
to give protection; others, to furnish a special breeding-place 
for the gemmules differentiated into the nucleus; and so on. 
When the gemmule was set free, it more and more had to be 
protected by special envelopes, and so arose spores. When all 
the gemmules free for reproductive purposes went into the spores, 
the protoplasm remaining after the spores were set free could 
no longer grow, and hence live, and thus in reproduction by 
spores, as in gregarines, the mother-cell was left as a corpse when 
this sort of reproduction was exercised. (Fig. 27, e.) 
But reproduction by binary division still continued, modified 
first as budding, where some of the reproductive gemmules were 
pinched off with a share of the cytoptasm. Here we must call 
attention to the fact that the zadtviduality of the cell does not de- 
pend on the number of idioplasm gemmutes in it, for all these, being 
undifferentiated, are, as it were, embryonic or alike and mutually 
autonomous.” They continually grow and divide, and two, result- 
ing from one, do not produce a different kind of effect, but only 
more work than one. Indeed, the effect produced is not seen until 
they differentiate, and so present the characteristics of the cell. 
This principle is extremely important for understanding the facts of 
Fertilization. It makes no difference whether the reproductive 
element set free contains ove or a million gemmules, except that 
in the former case it sakes longer to make as large a cell as the 
mother; in precisely the same way as it takes longer to raise a 
hydra from the unicellular egg than it does from the multicellular 
bud. The reproductive gemmules being now confined to the 
` nucleus, binary division resulted in nuclear division; so far as 
it was advantageous that a large: plasmodium-like cell should 
be produced, the new nuclei remained and nourished the common 
cell; and so far as the spreading of the cell over the habitat was 
of advantage, each daughter-nucleus took its half of the cyto- 
plasm, thus producing cell division. This subject will be con- 
tinued under the head of Karyokinesis. Continued binary division 
of the nucleus and the development of the products while the 
mother-cell remains undivided results in free cell formation (at 
least one variety of this). These cells often play the role of spores, 
ad what icol ipportange yhes this is the tai, the size of the 
re is reduçed in their number,—ż.e., to the number 
~ of divisions. . In a somier of the monads these spani. are so 
“ Tapi meho Arch. f. Mic. Anat., xxvi. i 
