Zoological Society. 443 
peculiar to peat-bogs are instanced as cases where it is not unlikely 
that organized substances are imbibed. Moreover, the author dwells 
upon the fact that itis only the root-cells which really assimilate in- 
organic substances ; he upholds the opinion that assimilation takes 
place in the very act of the primary absorption, and that thus there 
does not exist any which can be properly called crude sap; the 
assimilated matter derived from the roots is modified by the various 
organs into which it passes, according to their special character. He 
rejects in toto the idea of a circulation of the sap, regarding the pass- 
age of fluids through all plants as a mere distribution from cell to 
cell, such as takes place in wholly cellular structures. It appears to 
us that this hypothesis is too sweeping. ‘There can be no doubt that 
the ducts or large tubular forms of the tissue frequently open into 
each other after they have attained a certain age, thus forming 
continuous canals, and it is equally certain that these occur in the 
vascular bundles, especially in the wocd. There seems to be no 
reason to doubt that mere capillarity will cause the fluids to ascend 
in these ducts when a current is maintained by the evaporation from 
the leaves. With respect to a descending current, there is great 
likelihood that Profs. Schleiden and Mulder are right in denying it, 
and asserting that all the phenomena supposed to result from it are 
to be explained by the process of endosmosis, which is indeed the 
principal cause of the ascending current. We can hardly imagine a 
current upward and downward in the vessels; but in endosmosis 
there is an interchange,—a passage in both directions with an ulti- 
mate tendency to equilibrium. Careful experiments are still wanting 
on this subject. 
In the appendix to the translation are: A. Analytical papers ; 
B. A list of old trees; C. The extracts from the third German edi- 
tion of books 1 and 2 already referred to; and D. An article on the 
use of the Microscope from the ‘* Methodological Basis ’’ prefixed to 
the original work, but which is omitted in the translation in order to 
diminish the bulk of the volume. 
The volume is well illustrated wholly from the author’s own draw- 
ings, a rather unusual circumstance, but of course greatly adding to 
its value. 
No one interested in scientific botany should be without the work. 
PROCEEDINGS OF LEARNED SOCIETIES. 
ZOOLOGICAL SOCIETY. 
December 12, 1848.—R. C. Griffith, Esq., F.G.S., in the Chair. 
Dr. Melville communicated orally the first part of his paper 
‘‘On the Ideal Vertebra.”” He commenced by defining this as ‘ the 
most complete possible segment of the endo-skeleton,” or in the 
words of his friend Mr. Maclise, “‘ the plus vertebral quantity ;”’ and 
it was illustrated by a diagram showing the body, neural arch and 
