362 GENERAL VIEW OF THE HUMAN FUNCTIONS. 



exists a connection of an entirely reverse kind, between the Organic and Animal 

 functions; for the conditions of Animal existence render the former in great 

 degree dependent on the latter. In the acquisition of food, for example, 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 propul- 

 sion of the food along the alimentary canal of the former, requires a series of 

 operations in which Muscular contractility is required, the Nervous and Muscular 

 systems being together employed at the two extremes; and thus we see that the 

 change in the conditions required for the ingestion of food by Animals, has 

 rendered necessary the introduction of additional elements into the apparatus, 

 to which nothing comparable was to be found in plants. Again in the function 

 of respiration, as performed in Man and the higher animals, the Nervous 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 respiratory organs, are 

 chiefly occasioned by the contractility of a muscular organ, the heart. Such 

 movements, however, as are thus immediately connected with the maintenance 

 of the Organic functions, do not depend upon the will, and may even be per- 

 formed without our consciousness; they can scarcely be regarded, therefore, as 

 forming part of our proper Animal life; and the only essential difference which 

 they present, from those which are occasionally performed by Plants (especially 

 such as exhibit the transmission of the effect of a stimulus to some distance the 

 folding of the leaves of the Mimosa, or the closure of the fly-trap of the Dion^ea, 

 for example), consists in the instrumentality through which they are performed 

 this being in Animals a peculiar Nervous and Muscular apparatus, whilst in 

 Plants it is only a modification of the ordinary structure. 



373. From what has been said, then, it appears that all the functions of the 

 Animal body are so completely bound up together, that none can be suspended 

 without the cessation of the rest. The properties of all the tissues and organs 

 are dependent upon their regular Nutrition, by a due supply of perfectly elabo- 

 rated blood; this cannot be effected, unless the functions of Circulation, Respi- 

 ration, and Excretion be performed with regularity the first being necessary 

 to convey the supply of nutritious fluid, and the two latter to separate it from 

 its impurities. The Respiration cannot be maintained without the integrity of 

 a certain part^of the Nervo-muscular apparatus ; and the due action of this, again, 

 is dependent upon its regular nutrition. The materials necessary for the replace- 

 ment of those which are continually being separated from the blood, can only be 

 derived by the Absorption of ingested aliment; and this cannot be accomplished, 

 without the preliminary process of Digestion. The introduction of food into the 

 stomach, again, !s dependent, like the actions of Respiration, upon the operations 

 of the muscular apparatus and of a part of the nervous centres ; and the previous 

 acquirement of food necessarily involves the purely Animal powers. Now it 

 will serve to show the distinction between these powers, and those which are 

 merely subservient to Organic life, if we advert to the case, which is of no un- 

 frequent occurrence, of a Human being, deprived, by some morbid condition of 

 the brain, of all the powers of Animal life, sensation, thought, volition, &c. ; 

 and yet capable of maintaining a Vegetative existence, in which all the organic 

 functions go on as usual that division of the nervous system which is concerned 

 in the movements whereon some of them depend, not being yet affected by the 

 morbid influence. It is evident that we can assign no definite limits to such a 

 state, so long as the respiratory movements are sustained, and the necessary 

 food is placed within reach of the grasp of the muscles that will convey it into 

 the stomach : as a matter of fact, however, it is seldom of long continuance, 

 since the disordered state of the brain is sure to extend itself, sooner or later, to 



