of certain Birds of Cuba. 7 
he may also be supposed by some to have understood this doc- 
trine of variation in animal structure; but it is easy to show, 
that although this extraordinary man understood it to a certain 
degree, he confined himself in the passage in question to the 
division of organs,—a course of reasoning that led him quite 
away from the conclusions he would indubitably have arrived 
at, had he followed the variation of general structure. Still I 
shall not be surprised if the originality of even this principle be 
some 
long and those with short beaks, into those with crests and those without crests, &c. Kc. 
This is the most arbitrary, and therefore, I suppose, the oldest of all modes of arrange- 
ment; and, as Aristotle expressly says, it is so easy, that any one may adopt it. L 
have said a few words on its merits in the Hore Entomologice, p. 188; but the truth 
is, that proceeding entirely on the notion of division, and not of aflinity, it is a method 
which is applicable to all sciences whatsoever, as much as to zoology. It has nothing 
to do with the natural system, which must of course depend upon affinities. 
3. Thirdly, Organs may be arranged according to their analogies (xar’ avadoyiav), as, 
for example, when we compare the claw with a hoof, or the feather of a bird with the 
scale of a fish: for, says he, what a feather is to the bird, a scale is to the fish. Had he 
said, that animals instead of their organs may be arranged according to their analogies, 
it is evident that he would have then distinguished relations of analogy from those of 
affinity, Aristotle being too profound a logician to use the one word for the other. But 
the instances given by him to explain his doctrine, prove that the word avaAoyie in this 
place signifies comparison of form rather than resemblance in form. So that the proper 
translation of the passage is, that similar organs may be arranged according to their 
difference of structure, as when we compare a claw with a hoof, or, as he himself does 
in another part of his work, the wing of a bird with the fore-foot of a quadruped. It 
does not appear in this place very clear, whether Aristotle intended to apply his ma- 
thematical axiom, and to say, that organs being arranged in this manner, the animals 
may also. Although such a mode of reasoning will not lead to any false conclusions, 
it is far from being an obvious mode, at that early period of natural history, for him to 
have adopted. If he did not intend to call his axiom into action, he only stopped at 
the resting-place of comparative anatomists in general, who often trace the modifications 
of an organ without ever thinking of their use towards natural arrangement. If, on the 
other hand, he did intend to apply it, my claim to the priority of arranging animals by 
their variation of structure, would at first sight seem to be in danger. But it remains 
to be considered, whether in this event his zoological arrangement (making allowance 
for 
