462 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1907. 
A striking and even amusing example of its exposition and its failure 
I have previously drawn attention to. 
Professor Huxley, in his excellent “ Introduction to the Classifi- 
cation of Animals” (published in 1869), in his first chapter, ‘“ On 
Classification in General,” concluded a consideration of Cuvier’s law 
of the correlation of structure with the following paragraphs: 
Cuvier, the more servile of whose imitators are fond of citing his mistaken 
doctrines as to the nature of the methods of paleontology against the conclusions 
of logic and of common sense, has put this so strongly that I can not refrain 
from quoting his words.?% 
But I doubt if anyone would have divined, if untaught by observation, that 
all ruminants have the foot cleft, and that they alone have it. I doubt if any- 
one would have divined that there are frontal horns only in this class; that 
those among them which have sharp canines for the most part lack horns. 
However, since these relations are constant, they must have some sufficient 
cause; but since we are ignorant of it, we must make good the defect of the 
theory by means of observation; it enables us to establish empirical laws, which 
become almost as certain as rational laws, when they rest on sufficiently re- 
peated observations; so that now, whoso sees merely the print of a cleft 
[fourchu] foot may conclude that the animal which left this impression rumi- 
nated, and this conclusion is as certain as any other in physics or morals. This 
footprint alone, then, yields to him who observes it, the form of the teeth, the 
form of the jaws, the form of the vertebree, the form of all the bones of the 
legs, of the thighs, of the shoulders, and of the pelvis of the animal which has 
passed by; it is a surer mark than all those of Zadig. 
The first perusal of these remarks would occasion surprise to some 
and immediately induce a second, more careful reading to ascertain 
whether they had not been misunderstood. Men much inferior in ca- 
pacity to Cuvier or Huxley may at once recall living exceptions to the 
positive statements as to the coordination of the “ foot cleft ” with the 
other characteristics specified. One of.the most common of domesti- 
cated animals—the hog—may come up before the “ mind’s eye,” 1f not 
the actual eye at the moment, to refute any such correlation as was 
claimed. Nevertheless, notwithstanding the fierce controversial litera- 
ture centered on Huxley, I have never seen an allusion to the lapse. 
And yet everyone will admit that the hog has the “ foot cleft ” just 
as any ruminant, but the “ form of the teeth ” and the form of some 
vertebrae are quite different from those of the ruminants and, of 
course, the multiple stomach and adaptation for rumination do not 
exist in the hog. That any one mammalogist should make such a 
slip is not very surprising, but that a second equally learned should 
follow in his steps is a singular psychological curiosity. To make the 
case clearer to those not well acquainted with mammals, I may add 
that because the feet are cleft in the same mamer in the hogs as in 
@‘*Ogsemens fossiles,” ed. 4me, tome Ir, p. 184. 
