24 
TRANSACTION'S OF THE TEXAS ACADEMY OF SCIENCE. 
employment being largely dependent on the firmly erect posture, 
changes in the feet, legs, pelvis, and spinal column followed, in the 
way of spontaneous variation, of inherited acquired characters, or of 
both combined. Again, the hand superceding the powerful canine teeth 
in the matter of offense, of defense, and in other ways, the massive jaw 
of man’s ape-like progenitors was necessarily modified and reduced. 
The other line of departure, which Darwin does not coordinate with 
that beginning in hand -development, though it must have been closely 
related to it, began in a great increase in the weight, size, and conse- 
quently, owing to the confining skull, in the convolutions of the brain. 
And finally the increased weight of the brain, together with the erect 
posture, contributed to the modifications in the shape of the skull and 
spinal column. 
Darwin’s order has not been universally accepted, and several con- 
jectures, more or less plausible, both as to the order of development 
and as to the factors conditioning it, have been made. Nevertheless, in 
view of the evidence he cites, and of further confirmatory evidence that 
will appear in this discussion, I believe that Darwin’s account can be 
shown to be essentially sound. In this connection it may not seem 
unimportant that the process of humanization was largely conditioned 
by changes in the hand, the jaw, and the spinal column. Of that, 
something more later. 
Coming to .the second group of distinctions, -the broad fact that there 
is some mental difference between animals and men is too patent for 
denial, and has long been recognized and commonly asserted in the 
form of the statement that men alone possess reason. But when it 
comes to be more clearly seen that animals have some sort of mind and 
conscious life, the precise definition of what is meant by “reason” is 
found to be no easv matter. 
> 
For a long time, and by many authors, the attempt was made to show 
that men have general ideas and that animals are without them. But 
recent investigations, consisting chiefly in a careful study of the higher 
animals, made by Romanes and others, have shown beyond peradventure 
that animals also have general ideas. From a large body of eAfidence 
given by many authors I reproduce two descriptions, quoted by Romanes, 
the former from Darwin, the latter from Leroy: “When I say to my 
terrior, in an eager voice (and I have made the trial many times), ‘Hi, 
Hi, where is it?’ she at once takes it as a sign that something is to be 
hunted, and generally first looks all around, and then rushes into the 
nearest thicket, to scout for any game, but finding nothing, she looks 
up into any neighboring tree for a squirrel. Now, do not these actions 
clearly show that she had in her mind a general idea, or concept, that 
