118 



MAMMALIA. 



the sacred volume, that "no man, by taking thought, 

 can add a cubit to his stature," and there is a great 

 deal of philosophical truth in the saying. The mind 

 of a human being has not the least coutroul over the 

 character or appearance of any one part of the human 

 body, unless in so far as experience may have taught 

 it to use physical means for such a purpose ; and if 

 this is the case with regard to the matter and mate- 

 rial structure of the body with which it is so inti- 

 mately though mysteriously connected, much more 

 must 'it be the case with all matter external of the 

 body. , . 



The principle involved in this is not an unimportant 

 one. We know nothing substantive but matter, and 

 can form no notion of any kind of substance except 

 material substance, and therefore our conceptions of 

 the nature of mind, and also of the nature of that 

 which we call animal life, must be made up of nega- 

 tives : we can tell what they are not, but we cannot 

 tell what they are ; and as the negative in respect of 

 both is much the same with relation to substantive 

 matter, it is very desirable that we should have some 

 means of discriminating between the two, and under- 

 standing precisely the difference between them ; for 

 if we do not, we are in constant danger of confound- 

 ing them together ; and as a good many of the actions 

 of those mammalia which have the most sensation 

 and the most numerous resources have a great deal 

 of similarity to actions performed by human beings, 

 \ve are in great danger of considering the difference 

 between mind and animal life as being a difference 

 in degree only, and not an essential difference in 

 nature. 



When, however, we view the relations in which 

 the two stand to matter, and the laws of matter, we 

 readily perceive the difference. Mind, as we have 

 said, has the faculty of knowing matter ; but it can- 

 not, without the instrumentality of some material 

 means, the employment of some material agent of 

 which it has acquired a knowledge by experience, 

 produce the least effect upon matter, or suspend or 

 counteract, to the smallest extent, even the most 

 simple physical law. It has the knowledge of mat- 

 ter, and it is the nature of knowledge that it does 

 not perish with that which is known. New objects, 

 indeed, are so repeatedly drawing our attention in 

 this world, and we have such a scramble to supply 

 the real and artificial wants of the body, and all those 

 other demands which the customs of society impose 

 upon us, that we do not heed many things that were 

 once known to us. But, even in these cases, there 

 is no absolute loss or oblivion of the knowledge, for 

 the most .trifling circumstance will, if we were once 

 acquainted with it, return, as we say, to our recollec- 

 tion, and that frequently by means which we cannot 

 understand. All material things can pass into new 

 forms, by entering into new combinations, and when 

 the new form is assumed, the old one is gone for ever, 

 and can no more be recalled than the noon of yester- 

 day can be brought back to illuminate the midnight 

 of to-morrow. But knowledge, of whatsoever it may 

 be the knowledge, cannot thus be obliterated or cease 

 to exist by passing into any new combination. It is 

 true that we can and do, in many instances, obtain 

 new knowledge by combining together, Or rather 

 comparing together, different portions of knowledge 

 previously acquired. But this bears no analogy what- 

 ever to what takes place in combining matter, for the 

 new knowledge is not composed of the previous 



knowledge which leads to it, and the previous know- 

 ledge is not lost, or clouded, or confounded by the 

 additional knowledge to which it has pointed out the 

 way. Every portion of it stands as entire and un- 

 mixed as if nothing but itself were known ; nor are 

 there any means by which we can contrive to bury 

 in oblivion that which we once knew ; and every one 

 must have felt that the more we labour to forget any 

 thing, we just remember it the better. 



The characteristic of mind, that in which alone 

 it does or can display itself, is thus of an immortal 

 nature, and cannot be lost or have its properties ob- 

 literated in a compound, as can happen to every kind 

 of matter with which we are acquainted. A portion 

 of knowledge cannot, in fact, be a compound ; for 

 whatever be the subject known, the knowledge of it is 

 one and simple. The ancients, for instance, knew 

 atmospheric air as a simple substance, and water as 

 another, and from this supposed simplicity they called 

 both elements of mere compound substances. We 

 know atmospheric air as a compound of oxygen and 

 nitrogen, and water as a compound of oxygen and 

 hydrogen ; and we also know that, as they exist in 

 nature, both of these, generally speaking, contain 

 other matters. But our knowledge of air or of water 

 is not, in itself and considered as an act or state of 

 the mind, any more compound than the knowledge 

 which the ancients possessed of the same substances, 

 when they believed them both to be simple and ele- 

 mentary. 



Knowledge is, therefore, in its very nature simple 

 incapable of combination in the sense in which we 

 apply that term to matter, and not material ; and it 

 follows, by necessary consequence, that knowledge is 

 immortal that is, it cannot be destroyed by the 

 operation of any cause which affects matter, or by all 

 such causes acting together that it can yield to 

 nothing save the power of One who could command 

 matter to be where matter did not previously exist, 

 and command matter to depart and leave nothing in 

 its stead. 



Now, if the only manifestation which we have of 

 mind, namely that of knowing, or being possessed 

 of knowledge, is of an indestructible anid, therefore, 

 immortal nature, it must follow that this must be an 

 essential attribute of mind itself: because whatever 

 is known only from the demonstrations that we have 

 of it in its effects as an active principle, must neces- 

 sarily be regarded as possessing any one property, 

 whatever it may be, which is common to and insepar- 

 able from all those effects. But all the evidences 

 which we have or can have of the existence of the 

 human mind are of an immortal nature, being know- 

 ledge, and nothing but knowledge ; and, conse- 

 quently, from this alone, and without any other argu- 

 ment or proof, natural or revealed, it is impossible for 

 us to come to any other conclusion than that the 

 human mind is of an immortal nature, not resolvable 

 into parts, or decomposable by the operation of any 

 or of all the secondary causes or energies of created 

 existences that can be named, subject only to the 

 direct fiat of its Maker ; and as we can by possibility 

 know nothing of the work of creation, or production 

 without materials, so we can know nothing of the 

 counter-work of annihilation in the ceasing to be of 

 that which once existed. 



This a point, the clear understanding of which is 

 of the utmost importance, if we wish to possess 

 rational views on the subject of animal physiology. 



