s conduits, a l'aide desquels les corps
animes qui les secretent et les faconnent, se logent, puisent
et charriant leurs aliments, deposent et isolent les matieres
excretees."

And again:--

"A fin de completer aujourd'hui l'enonce du fait general, je
rappellerai que les corps, doue des fonctions accomplies
dans les tissus des plantes, sont formes des elements qui
constituent, en proportion peu variable, les organismes
animaux; qu'ainsi l'on est conduit a reconnaitre une immense
unite de composition elementaire dans tous les corps vivants
de la nature."[1]

[Footnote 1: "Mem. sur les Developpements des Vegetaux," &c.--"Mem.
Presentees." ix. 1846.]

In the year (1846) in which these remarkable passages were published,
the eminent German botanist, Von Mohl, invented the word "protoplasm,"
as a name for one portion of those nitrogenous contents of the cells
of living plants, the close chemical resemblance of which to the
essential constituents of living animals is so strongly indicated by
Payen. And through the twenty-five years that have passed, since the
matter of life was first called protoplasm, a host of investigators,
among whom Cohn, Max Schulze, and Kuehne must be named as leaders, have
accumulated evidence, morphological, physiological, and chemical, in
favour of that "immense unite de composition elementaire dans tous les
corps vivants de la nature," into which Payen had, so early, a clear
insight.

As far back as 1850, Cohn wrote, apparently without any knowledge of
what Payen had said before him:--

"The protoplasm of the botanist, and the contractile substance
and sarcode of the zoologist, must be, if not identical, yet
in a high degree analogous substances. Hence, from this point
of view, the difference between animals and plants consists
in this; that, in the latter, the contractile substance, as
a primordial utricle, is enclosed within an inert cellulose
membrane, which permits it only to exhibit an internal motion,
expressed by the phenomena of rotation and circulation, while,
in the former, it is not so enclosed. The protoplasm in the
form of the primordial utricle is, as it were, the animal
element in the plant, but which is imprisoned, and only
becomes free in the animal; _or_, to strip off the metaphor
which obscures simple thought, the energy of organic vitality
which is manifested in movement is