398 On the Aériferous Vesicles of the Utricularize. 
We thus see the utricles play the part at once of organs of 
respiration and of a hydrostatic apparatus. These organs there- 
fore do not appear at a given moment and for a particular pur- 
pose, but as a natural consequence of the anatomical structure 
of the plant and the action of the surrounding mediim. I 
shall take the liberty of adding here a passage from a work by 
Schleiden, already cited (Grundziige &c.), which relates to the 
idea that I have just expressed :— 
“What is most interesting in the life of the plant,” says 
Schleiden, “is its dependence upon the life diffused over the 
earth in general. It must be admitted that im the forces upon 
which depend meteorological phenomena and the formation of 
organs and of organisms (Bildungstrieb, &e.) we have already, as 
given in a necessary manner, the cause which makes a certain 
insect be produced during the flowering of a certain plant—an 
insect the life of which depends in its turn upon its nutrition 
by the nectar secreted by this plant; then, in absorbing this 
liquid, the insect transfers the pollen to the stigma, and thus 
assures the continuance of the vegetable species which furnishes 
it with its nourishment. -When ye consider the coincidence of 
phenomena for an isolated plant, it often appears to us to de- 
pend upon pure chance; for example, the coincidence of wind 
with the flowering of the Abictinex, of the fall of rain with that 
of Ambrosinia Bassiw*, of the movement of the water with the 
expansion of the flowers of Valisneria; but these coincidences 
are only necessary consequences of the same primitive forces 
which manifested themselves in the evolution of our planet.” 
The totality of the forms in which life manifests itself upon 
the earth during a given epoch appears to us thus like a magni- 
ficent mosaic, of which the different pieces brought together 
mutually determine their nature. 
* The spathe of Ambrosinia Bassii presents the form of a trough, and 
thus swims on the surface of the water. The spadix, which rises in this 
spathe, divides it into two parts by means of a membranous wing which 
surrounds the spadix and is attached to the spathe; the lower compart- 
ment contains the anthers, and the upper one a single ovary : between the 
two compartments there is a little aperture in the separating partition. 
Fecundation cannot take place unless at the period of flowering rain falls 
into the spathe. The water then fills the lower compartment, and its level 
gradually rises up to the ovary in the upper compartment; the pollen, 
which floats on the surface of the water, thus comes in contact with the 
organ which it has to fecundate. 
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