INSTINCT AND REASON. 8Y 
perceptions ; and thus exhibiting the semblance of a kind of 
experience by which they are enabled to profit. This, in 
fact, constitutes the rationale of that plasticity of their 
mental emotions, which, while it corresponds to the plasticity 
of their organic forms, is apt to deceive those who imagine 
that they are endowed with reasoning powers of the same 
kind as those of Man, because their instinct is thus, within 
very narrow limits, adaptive, and, therefore, simulates on a 
small scale the operations of Reason. But all this is in 
reality merely sensuous in its nature, and has nothing in 
common with the higher manifestations of memory, expe- 
rience, and inference, as exhibited by reasoning Man. 
In the second category, that of the higher animals, we 
have also indications of a certain teachableness, within defi- 
nite limits, in matters, not indeed of morality or respon- 
sibility, im any true sense, or even in true intellectual 
exercise in its most rudimentary form; but in matters 
relating chiefly to that which is one of the real and sole 
subjects of instinct, viz., self-preservation (avoidance of 
danger or of pain) and mattets accessory to nutrition and the 
appetite for food and drink (in the form of rewards: for 
obedience and docility). For it is these impulses which 
chiefly reconcile such animals to the mechanical performance 
of tasks which only the superior will of the human teacher 
can influence them, contrary to their nature, to strive to 
accomplish. 
For, be it observed, Thought does not enter into any of 
these mental operations of animals. For even in the highest 
phenomena which spring from this teachableness or docility, 
there is exhibited nothing more than a certain plasticity ot 
mental endowments which is affected and brought into play 
by habit and environment, just as their bodies possess such 
an inherent plasticity which is affected by similar, or, more 
properly speaking, correlative, influences. And although such 
phenomena appear to give to the evolution school the 
countenance which they seek, they are in reality mere 
accessory manifestations of instinctive powers with a purely 
corporeal motive, which will be shown, as we proceed, to 
leave quite untouched the fundamental principles which 
externally distinguish between animal instinct and human 
Reason. The plasticity, deed, even where it exists, 1 
acknowledged by all to have very narrow limits, and, in its 
highest development, to result in phenomena of so simple 
and so humble a character, that, if observed in a young child, 
would scarcely redeem it from the imputation of idiocy. 
