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fess, are, at all events, clear and decided. It would be pleasant if we 
could say as mucb for their accuracy. Professor Owen or Mr. C. Blake, we 
know not on whom the paternity of the definition lies, defines the term 
u animal ” as follows : — “ The name of the higher division or kingdom of 
organised beings distinguished by endowments of sensation and voluntary 
motion, superadded to the organic functions which animals possess in 
common with plants.” The writer having given this cumbersome and 
valueless explanation, proceeds to deal with the objections which may be 
urged against it, and to our minds in a very unsatisfactory manner. He 
says that it might be thought that certain confervse have the power of 
locomotion, and that in some plants a species of irritability is found, 
but these faculties in the instances referred to are more imaginary than 
real. No one, he says, can mistake the locomotion of a vegetable for that 
of an animal organism ; the notion of vegetable sensation results from a 
confusion of the terms a irritability ” and u sensation.” Such an ex cathedra 
denunciation of the observant and discriminating power of those who 
are too cautious to pronounce at once as to the animality or vegetality of 
an organism, has a weight of its own, but its force is that of brutum fulmen. 
Is it possible that the writer can assert for one moment that the locomotion 
of the sponge — whose animal character is undoubted — is superior to that of 
the volvox or to that of the diatomacese as pointed out by Schultze P If so 
we must give up the argument. Then again, when he talks so flippantly 
about confounding sensation with irritability, can he inform us what 
exact significance he attaches to either of these terms ? If he can, he will 
do us a signal service by giving us the information, and he will confer a 
great boon on Modem Physiology. Of what value is zoological definition 
when dependent on asserted qualities which he who defines is unable to 
offer an intelligible account of? How, for instance, can we distinguish 
irritability from sensation when we know that in the case of a decapitated 
frog, the so-called property of irritability is to all appearance that of sensa- 
tion ? Professor Owen smiles at the untutored physiologist who can dream 
of comparing the movement of the sensitive plant with the motion of an 
animal, for, says he, u Experiment has shown that the intumescent parts of 
the mimosa , in which the irritable property is concentrated, move the leaf 
by an extension of cells and not by a contraction of fibres.” This is 
plausible enough but it does not stand the test of analysis. How can 
Professor Owen suppose his li extension of cells ” to take place without con- 
traction P Surely if the movement of a continuous mass displays extension 
in one direction it must exhibit contraction in another, unless we suppose — 
which we cannot in the case in point— that a general expansion as by heat 
occurs. Moreover we would ask Professor Owen to bear in mind that the 
so-called contraction of his animal “ fibres ” is attended with a lateral 
extension. However, if we yield all these objections to the writer’s dogma 
we still have the important fact that in the movements of the Amoeba, 
there is no contraction of fibres , for the simple reason that there are no 
fibres to contract. This one fact is quite sufficient to refute the writer’s 
argument. The other statements in the article in question are certainly 
opposed to our belief. We have yet to learn that every animal is provided 
with i( an internal cavity ” for digestion, as we know that certain species 
