~ 
332 NATURE OF SPONGES. 
all motion ; the external form, and in some measure 
the appearance of the texture approximate most 
closely to vegetation, but still the substance and 
integral composition is animal. These animals 
therefore are the last grade in creation before we 
pass over to the class of vegetables. Still it must 
be remembered that no tribe can in propriety be 
termed intermediate physiologically—not combi- 
ning the qualities ofboth classes, except to superficial 
appearance, and as it were by simulation of charac- 
ters not actually possessed.—It would seem therefore 
by the above statements that animality is not 
constituted by forms which we habitually call 
animals, the polypi or architects of corals for 
instance, but by the production of substance which 
is chemically animal, and yet not assuming forms 
recognisable as animals. It may now be asked 
however, and with the utmost propriety, how the 
substance of these productions is derived and 
assimulated, and yet no absolute animal, or creature, 
or direct agent, be discernible? It must be con- 
fessed that this question cannot be answered by 
the means of occular or of physiological enquiry, 
but that on the contrary we are obligated to look 
to the analogy of plants, likewise destitute of 
ostensible and circumscribed beings, and to reflect - 
that there a power exists of abstracting nourishment 
from the earth and air and of assimilating the 
particles, and so in like manner it must be con- 
eluded, that the tribe of sponges are empowered 
with the capacity of drawing atoms for the 
sustenance of their peculiar structure from the 
medium wherein they live.—As in vegetables, so 
in the sponges, the mere vital property operates 
without the aid of any demonstrable agent, and ~— 
probably only on chemical principles. _ 
Notice of a peculiar faculty in Man and certain 
animals.—There is an extraordinary power pos- 
