ae oe 
es 
On the so-called Biogen Liquid. 405 
Starting now from the structure of the egg and knowing it to 
be identical in its constituent elements throughout the whole ani- 
mal kingdom, the doctrine of its crystallization from a mother- 
liquid refutes itself. The idea that the vitellus is precipitated, or 
is crystallized, is indeed very strange. Is not this the distinction 
which we make between the inorganic kingdom and the organic 
kingdom, that the former is crystallized, while the latter is or- 
ganized. 
And then as to the physical characters of this biogen liquid, 
and the method of distinguishing it from albumen, not a word i 
said. All that has been done is the substitution of a name, the 
thing newly named is hidden from the eyes of physiologists. To 
explain the formation of eggs in the animal kingdom, Mr. D. 
thus finds himself obliged to procure the intervention of a liquid 
of which he knows nothing,—a liquid which would make the 
function of the ovary of secondary importance,—a liquid which 
would substitute itself for the vital action of the organism, an ac- 
tion which physiology explains,—in fine, an occult liquid, which 
sound philosophy disowns. eden 
'o oppose such a liquid to the vital action of the organism in 
the procreation of the substance, from which new individuals 
arise, is to go out of the domain of science. Mr. D. moreover 
has found that his biogen liquid runs through various modifi- 
cations. This liquid then has no permanent character, it Is under 
the influence of something beyond it, which produces it in its turn. 
Anatomy and physiology are our guides in our embryological 
researches ;—one confirms the other. Remaining within these 
limits, it was not necessary to go beyond the bounds of sound phi- 
osophy, and to fancy a theory which rests upon nothing, which 
teaches nothing new, which explains nothing, and which stands 
apart, isolated from physiology. see 
Thus the theory of biogen, applied to the egg of Ascidia, is not 
€ven probable ; applied to the animal kingdom it is absurd. 
V. § 1. Prepossessed by the false notion that the vitellus is 
formed by condensation, Mr. D. compares the formation of eggs to 
that of the celestial bodies, according to the nebular hypothesis. 
t in order that a comparison of one phenomenon with some 
other phenomenon may be established, it is necessary that the one 
With which the comparison is made, should be perfectly demon- 
ted,—it must be a law ora principle. — ; 
Now the author forgets that the question of the condensation 
of the heavenly bodies according to the nebular hypothesis, is 
road of the most controverted questions. ‘eo 7 is ate 
now nothin itively respecting the origin of the stars. Has 
€ matter of ahah ihe ge eoeapoeed. been diffused through- 
Out space under the form of what has been called nebule, and 
