ORGANIC EVOLUTION RECONSIDERED. . 129 
Darwin believed that every part of the body gave off “ gem- 
mules,” or very minute bodies, which were collected into the 
ovum, and thus the ovum came to be a sort of abstract of the 
whole body—hence the resemblance of offspring to parents, . 
since the development of the ovum was but that of the gem- 
mules. Some of the gemmules might remain latent for genera- 
tions, and then develop; hence that resemblance often-seen to 
ancestors more remote than the parents (reversion). This is a 
very brief account of Darwin’s hypothesis of pangenesis. 
This writer, however, never accounted for variations. He 
spoke of variations as “spontaneous,” meaning, not that they 
were supernatural, but that it was not possible to assign them 
to a definite cause. To account for variation has naturally been 
the aim of later writers. How neo-Lamarckianism does this 
has been already considered. We now give the views of Brooks 
on this and other points in connection with organic evolution. 
This thinker, like Weismann, looks to the fertilized ovum 
for an explanation of the main facts; but Brooks refers the 
origin of variations to the influence of the male cell. This is, 
of course, a pure hypothesis, but it is in harmony with many 
facts which were in need of explanation. It had been noticed 
by Darwin that variations of all kinds were most apt to arise 
upon alteration in the conditions under which an animal 
lived. Brooks also believes in gemmules, but does not think 
they are. given off from all parts equally or at all times, but 
that they are derived from those parts most affected by the 
change of surroundings; and since this would influence parts 
much when for the worse, variation would coincide with suf- 
fering or need; hence those very parts would vary, and so pre- 
pare for adaptation, just when this was most called for by the 
nature of the case. But the male sexual element, it has been 
shown, is more liable to variation than the ovum; hence the ex- 
planation of what Brooks believes to be a fact, that it is the 
sperm-cell that generally is responsible for variation, since it 
chiefly collects the gemmules. 
The author of this theory points to parthenogenetic forms 
being less variable, as evidence of the truth of his view. To 
introduce a male cell is to impart vast numbers of new gem- 
mules, and thus induce variability. This hypothesis would ex- 
plain why the female represents what is most fundamental and 
ancient in the history of psychological development, and the 
male what is associated with enterprise—in a word, the female 
preserves, the male originates, in the widest sense. 
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