622 REVIEW—BRIDGEWATER TREATISES, NO. 5. 
and motives which animate the quadruped and the bird; but 
how can we transport ourselves, even in imagination, into the 
dark recesses of the ocean, which we know are tenanted by mul¬ 
titudinous tribes of fishes, zoophytes, and mollusca ? How can 
we figure to ourselves the sensitive existence of the worm or the 
insect, organized in so different a manner to ourselves, and occu¬ 
pying so remote a region in the expanse of creation ? 
Without venturing to speculate on the perceptions of the 
animalcule, whose world is a drop of fluid, and whose fleeting 
existence, chequered perhaps by various transformations, is des¬ 
tined to run its course in a few hours, we will confine our in¬ 
quiries to the more intelligible intellectual phenomena displayed 
by the higher animals, where we can readily trace a gradation 
which corresponds with the development of the central nervous 
organ, or brain. 
That the comparison may be fairly made, however, it will be 
necessary to distinguish those actions which are the result of the 
exercise of the intellectual faculties from those which are called 
instinctive, . and are referrible to other sources. We will let 
the author speak for himself:— 
“ Innumerable are the occasions in which the actions of ani¬ 
mals appear to be guided by a degree of sagacity not derivable 
from experience, and apparently implying a foreknowledge of 
events which neither experience nor reflection could have led 
them to anticipate. We cannot sufficiently admire the provident 
care displayed by nature in the preservation both of the indivi¬ 
dual and of the species, which she has entrusted, not to the slow 
and uncertain calculations of prudence, but to innate faculties, 
prompting, by an unerring impulse, to the performance of the 
actions required for those ends. We see animals providing 
against the approach of winter, the effects of which they have 
never experienced, and employing various means of defence 
against enemies they have never seen. The parent consults the 
welfare of the offspring she is destined never to behold ; and the 
young discovers and pursues without a guide that species of food 
which is best adapted to its nature. All these unexplained and 
perhaps inexplicable facts we must content ourselves with class¬ 
ing under the head of instinct , a name which is, in fact, but the 
expression of our ignorance of the nature of that agency of which 
we cannot but admire the ultimate effects, while we search in 
vain for the efficient cause.” 
In all the inferior orders of the animal creation, where instincts 
are multiplied while the indications of intellect are feeble, the 
organ which performs the office of the brain is comparatively 
small. The sensitive existence of these animals appears to be 
