126 Analogy het^ween Animals and Vegetables 



upon any mechanical arrangement, and they are perfectly 

 unaffected by any external causes. We must, therefore, 

 refer them to some internal stimulus. I must confess that I 

 can see no difference between the muscular motions employed 

 in the act of deglutition during infancy and the motions of 

 the pistil of the tiger lily, or of the stamens in the <Saxifraga. 

 Both are produced by some internal impulse ; both take place 

 in the absence of all external agents ; both are exercised 

 without volition ; and both are performed to accomplish an 

 important effect in the economy of each. Since, then, it has 

 been shown that the former depend upon nervous action, the 

 latter, which closely resemble them, ought to be referred to 

 the same agent. On these grounds, I conceive that plants, as 

 well as animals, are possessed of nerves of motion. 



I have already made some observations on the ganglionic 

 nerves : these, 1 remarked, were incapable of communicating 

 perception or volition. Their office is to unite the whole sys- 

 tem together, and to regulate the functions of the stomach, the 

 liver, and other organs of digestion : in fact, they preside over 

 all those functions which maintain, or are essential to, life. 

 These nerves are capable of receiving impressions from their 

 appropriate stimuli, but of these impressions the mind is 

 never conscious : the food, for example, acts upon the sto- 

 mach, but we never feel its action ; the lacteals absorb the 

 chyle and transmit it to the veins, and the blood-vessels cir- 

 culate the blood to every part of the system, but of neither 

 of these operations have we any consciousness. The sensi- 

 bility, therefore, of the ganglionic nerves is of that kind 

 which is unaccompanied with perceptibility. When, how- 

 ever, the functions which depend upon them proceed with 

 proper vigour and regularity, the result is a universal feeling 

 of energy, elasticity, and pleasure, which is considered and 

 called the state of perfect health : but when, on the contrary, 

 the ganglionic nerves, and the functions over which they 

 preside, become disordered, the delightful feelings which we 

 denominate health entirely disappear, and others of a most 

 distressing character occupy their place j a general languor 

 and inertness seize upon the body, and the mind grows weak, 

 unsteady, and irresolute, and in more severe cases it often 

 becomes so irritable, gloomy, and desponding, as to render 

 life a state of almost insupportable wretchedness. It has been 

 stated by some writers, with regard to vegetables, that their 

 growth, and the other changes which take place in them, are 

 the effect of mechanical and chemical actions alone ; so that, 

 from this view, the life of plants would seem to consist in a 

 physical and not a vital connection of their different functions : 



