74 GENERAL VIEW OF 1*HE FUNCTIONS. 



from Conception, and the Reasoning Faculties, which are still more closely 

 dependent upon Impressions made from without, on the other. For the phe- 

 nomena of Insanity are continually presenting to us instances of the disorder 

 of these powers, without any corresponding disorder of the operations, which 

 intervene between them and the external world ; and such disorder is often 

 (perhaps uniformly) coincident with some morbid condition of the brain. In 

 regard to the Moral Feelings and Emotions, again, it would seem equally 

 impossible to separate these by a distinct line, from the lower passions and 

 instinctive propensities, which are still more closely connected with material 

 changes ; and the daily experience, even of a person in ordinary health, reveals 

 to him how strongly the emotional conditions of the mind are influenced by the 

 state of the organic functions ; and how powerfully, on the other hand, the 

 latter are reacted on by the former. These, being phenomena which strictly 

 form a part of the Life of Man, evidently belong to the domain of the Physi- 

 ologist ; and no speculative views can (or, at least, ought to) affect our reasoning 

 from facts. 



80. The operations of the Mind and of its instruments, taken collectively, 

 constitute what are known as the Functions of Jlnimal Life. Those most ob- 

 viously connected with the bodily fabric, are Sensation and spontaneous Motion; 

 for these we find special instruments provided, the organs of sense and the 

 muscular apparatus. Both these, with the nervous system itself are composed, 

 like other parts of the fabric, of organized structure, which does not differ essen- 

 tially from that of the apparatus of Vegetative life, either in the mode of its 

 first production, or in that in which its integrity is maintained, and its activity 

 preserved. The conditions requisite for these objects will be presently dis- 

 cussed. But, although the functions of Animal life may be regarded as in 

 themselves completely isolated from those of Organic life, the latter merely 

 supplying the conditions of the former, by keeping (so to speak) their instru- 

 ments in good order, yet there are certain links of connection between the 

 two, which render the latter equally dependent on the former. Thus, in re- 

 gard to the acquisition of food, the Animal has to make use of its senses, its 

 psychical faculties, and its power of locomotion, to obtain that, which the 

 Plant, from the different provision made for its support, can derive without any 

 such assistance. Moreover, the propulsion of the food along the alimentary 

 canal is effected by a series of operations, in which the Nervous and Muscular 

 systems are together involved at the two extremes, whilst simple Muscular 

 contractility is alone employed through the greater part of the intestinal canal. 

 Thus, the change in the condition required for the ingestion of food by Ani- 

 mals, has rendered necessary the introduction of an additional element in the 

 apparatus, to which nothing comparable was to be found in Plants. Again, 

 in the function of Respiration, as performed in the higher Animals, the Ner- 

 vous and Muscular systems are alike involved ; for the movements by which 

 the air in the lungs is being continually renewed, are dependent upon the 

 action of both ; and those by which the blood is propelled through the respi- 

 ratory organs, are chiefly occasioned by the contractility of a muscular organ, 

 -the heart. But in regard to the simple contractility of muscular fibre, upon 

 the direct application of a stimulus to it, which is the agent in the movements 

 of the heart and of the alimentary canal, it may be remarked, that it does not 

 differ in any essential degree from that which is Avitnessed in many Vege- 

 tables ; and that it strictly belongs, therefore, to the functions of Organic life. 

 And with respect to those concerned in the act of Respiration, as well as those 

 which govern the two orifices of the alimentary tube, it will hereafter appear 

 that they result, equally with the former, from the application of a stimulus ; 

 and that they may be performed without any consciousness on the part of the 

 individual (though- ordinarily accompanied by it) : the difference being, that 



