CASPAR!" ON THE VESSELS OF PLANTS. 
365 
none the less that amongst these evascnlar plants are included genera 
which have been usually regarded as possessing vessels of unusual 
length and diameter, as, for example, the Banana (stem), Nelumbium , 
and the Water Lilies. 
The above paper, of 34 pages, Dr. Caspary tells us is preliminary. 
A more complete essay upon the subject of vascular bundles he hopes 
to publish at some future time. It suffices, however, to enable us to 
form a tolerably fair estimate of the bearing of the principal points 
advanced, which, after all, seem to us considerably less important 
than at first sight might appear. The question hinges upon the 
definition of the vessel. If we strictly agree with Yon Mohl, that it 
must consist of a row of superimposed cells, which have become 
combined into a tube through the absorption of their cross walls, we 
must necessarily admit with Caspary, that, provided his observations 
are correct, many of the higher plants are evascular. 
On the other hand, it must be borne in mind that some Botanists 
have not accepted this definition. The late Professor Henfrey, in the 
‘Micrographic Dictionary’ (1856), says, “The term vessel is now 
“ generally contrasted with duct , to indicate a single, long tubular 
“ cell, with spiral deposits, in contradistinction to a canal formed of 
“ a row of short cells of similar character applied end to end and 
“ confluent.” Spiral vessels, he says further, though usually simple 
at first, “ ordinarily unite together by a kind of fusion; the conical 
“ extremities overlap to a certain extent, and thus the articulation 
“ is more or less oblique.” These confluent vessels “ pass insensibly 
“ into the ducts, which are similar confluent rows of cells with flat 
“ ends applied together.” Of course the presence of either ducts or 
vessels, thus distinguished, determined the vascular bundle in Pro¬ 
fessor Henfrey’s practice, as indeed in the practice of Botanists 
generally. But no one could be more fully aware of the very 
gradual transition between cell and vessel than Yon M ohl himself. 
He expressly says, “ Ho sharply defined line can be drawn between 
vessels and cells.” And the following passage, which we quote from 
his well-known “ Principles of the Anatomy, &c., of the Yegetable 
Cell” (Henfrey’s Translation, p. 2), must indicate pretty clearly the 
comparatively small importance in either a structural or physio¬ 
logical point of view, this eminent phytotomist must attach to Dr. 
Caspary’s observations. It maybe noted that Yon Mohl here speaks 
of vascular plants as the equivalents, not of one, but of both the 
sections ( 'planted fasciculares) of Caspary, in contradistinction to 
cellular plants as generally understood. 
“ The circumstances, that a plant is composed of cells alone, or 
“ also possesses vessels, have not that importance either in a syste- 
“ matic or a physiological point of view which De Candolle attributed 
“ to them when he used them for the primary division of the vege- 
“ table kingdom, into cellular and vascular plants, for these con- 
“ ditions do not run parallel with the total organization of plants, 
