FUNCTIONS OF ANIMAL LIFE. 371 



rate individuals, is necessary for the process; for the ova are liberated by one, 

 and the spermatozoa by the other, and the accidental meeting of the two pro- 

 duces the required result. In many Animals higher in the scale, the impulse 

 which brings the sexes together is of a purely instinctive kind. But in Man, 

 it is of a very compound nature. The instinctive propensity, unless unduly 

 strong, is controlled and guided by the will, and serves (like the feelings of 

 hunger and thirst) as a stimulus to the reasoning processes, by which the means 

 of gratifying it are obtained; and a moral sentiment or affection of a much 

 higher kind is closely connected with it, which acts as an additional incitement. 

 Those movements, however, which are most closely connected with the essential 

 part of the process, are, like those of deglutition, respiration, &c., simply reflex 

 and involuntary in their character; and thus we have another proof of the con- 

 stancy of the principle, that, where the action of the apparatus of Animal Life 

 is brought into near connection with the Organic functions, it is not such as 

 requires the operation of the purely animal powers, sensation and volition. 

 Thus, then, as it has been lucidly remarked, " the Nervous System lives and 

 grows within an Animal, as a parasitic Plant does in a Vegetable; with its life 

 and growth, certain sensations and mental acts, varying in the different classes 

 of Animals, are connected by nature in a manner altogether inscrutable to man; 

 but the objects of the existence of Animals require, that these mental acts 

 should exert a powerful controlling influence over all the textures and organs of 

 which they are composed." 



3. Functions of Animal Life. 



389. The existence of consciousness, by which the individual (le moi, in the 

 language of French physiologists) becomes sensible of impressions made upon 

 its bodily structure, and the power of spontaneously exciting contractions in its 

 tissues, by which evident motions are produced, are to be regarded as the cha- 

 racteristic attributes of the beings composing the Animal kingdom; although 

 their possession by many of the tribes which seem to have their most appropri- 

 ate place in that kingdom, is, to say the least, extremely doubtful. 1 Of the 

 movements exhibited by Animals, there are many which are no more to be re- 

 garded as indications of consciousness, than are those executed by certain plants; 

 being simply the expressions or manifestations of a peculiar kind of vital force 

 in the tissues by whose instrumentality they are performed. Such movements, 

 in the lowest tribes, probably bear a much greater proportion to the whole 

 amount of those exhibited by the beings, than they do in the higher; whilst 

 those which we may regard as specially dependent on a nervous system, appear 

 to constitute but a small part of their general vital actions. The life of such 

 beings, therefore, bears a much closer resemblance to that of the Vegetable, 

 than to that of the higher Animal. Their organic functions are performed with 

 scarcely more of sensible movement, than is seen in plants; and of the motions 

 which they do exhibit (nearly all of them immediately concerned in the main- 

 tenance of the organic functions), it is probable that many are the result of the 

 simple contractility of their tissues, called into action by the stimuli directly 

 applied to them. It is scarcely possible to imagine that such beings can enjoy 

 any of those higher mental powers, which Man recognizes by observation on 

 himself, and of which he discerns the manifestations in those tribes, which, 

 from their nearer relation to himself, he regards as more elevated in the scale 

 of existence. If we direct our attention, on the other hand, to the psychical 3 



1 See "Princ. of Phys., Gen. and Comp.," CHAP, v., Am. Ed. 



2 Here and elsewhere this term will be employed in its most extended sense, to desig- 

 nate all the mental operations, whether intellectual, emotional, or instinctive, of which 

 Man's nervous system is the instrument. 



