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 it is 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 ioto 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 wood. 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 phsenomena supposed to result from it are 

 to be explained by the process of eudosmosis, 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 w^anting 

 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 botanv should be without the work. 



PROCEEDINGS OF LEARNED SOCIETIES. 



ZOOLOGICAL SOCIETY. 



December 12, 1848.— R. C. GriflSth, 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 



