406 On the so-called Biogen Liquid. 
has it been gradually condensed around a nucleus to acquire its 
sphericity under the power of universal attraction, and to assume 
then a given movement and. a determined direction ?_ 
There is no astronomer who can answer this question in the 
affirmative. From the study of our globe we arrive at the idea 
that it has had a beginning, and that it was originally in a fluid 
state. Beyond this, all is conjecture. Reasoning from the earth 
to the stars, we acknowledge, for all, a beginning of which “we 
are 1gnorant. 
It is then a false generalization to compare the phenomena of ovu- 
lation with the theory of the condensation of the sidereal bodies. 
But let it be fora moment granted that the stars have been 
formed by the condensation of matter at first diffused. Where is 
the analogy between what ought then to take place, and what 
we witness in the formation of the egg? 
The point of departure of organized beings is a sphere—the 
sphere is the figure of the celestial bodies; this is the whole of the 
analogy! In that sphere which constitutes the egg, two liquids 
are brought in contact and having an affinity for each other, 
they combine and form the vitellus which, from the first, is dis- 
tributed equally throughout the whole sphere, less dense, it is 
true, at the beginning; but never showing the least tendency to 
centripetal motion, the least disposition to be precipitated around 
the germinative vesicle. There is never any retreat of the vitel- 
lus from the periphery towards the centre; there is no gravitation ; 
there isa molecular attraction in the interior of a sphere, there 
are two liquids which are associated together, and not one liquid 
creating another out of itself. 
hus then should the theory of the condensation of the heav- 
enly bodies be true, that of the eggs arising from biogen would 
not even be its analogue. Where is the biogen of the stars? No 
astronomer has had the hardihood to imagine a mother liquid, a 
gas, or any substance whatever preéxisting in space to create mat- 
ter, and to disappear after having undergone various modifications. 
§ 2. But Mr. D. stops not here.. After having found the great 
law of attraction at the bottom of the formation of organic bod- 
ges, he comes to the question of movement. ‘“ As soon,” he says, 
“as the egg enters upon its organic life, it begins to revolve.” 
‘There are, indeed, a few invertebrated animals in which the em- 
bryo is subjected to a rotatory movement within the envelop of 
* the egg. When one witnesses this for the first time, his thoughts 
naturally revert to the rotatory movement of the celestial bodies. 
But on looking deeper into the subject, he soon perceives the dif- 
ference. I have described the movements which take place 1m 
the embryo of a marine Planaria.* Ihave shown that there 1s 
*® Proc. of the ‘Amer. Assoe. for the Adv. of Sciences, Second meeting, held at 
i August, 1849. Cambridge, 1850. 8vo, p. 400. ; 
