290 LAY SERMONS, ESSAYS, AND REVIEWS. [xiv. 



to the brain as to a sort of reservoir. Hence they pass into the nerves and 

 are distributed to the muscles, causing contraction, or relaxation, according 

 to their quantity.&quot; 



Thus, according to Descartes, the animal body is an auto 

 maton, which is competent to perform all the animal functions 

 in exactly the same way as a clock or any other piece of 

 mechanism. As he puts the case himself: 



&quot; In proportion as these spirits [the animal spirits] enter the cavities of 

 the brain, they pass thence into the pores of its substance, and from these 

 pores into the nerves ; where, according as they enter, or even only tend 

 to enter, more or less, into one than into another, they have the power of 

 altering the figure of the muscles into which the nerves are inserted, and 

 by this means of causing all the limbs to move. Thus, as you may have 

 seen in the grottoes and the fountains in royal gardens, the force with 

 which the water issues from its reservoir is sufficient to move various 

 machir/es, and even to make them play instruments, or pronounce words 

 according to the different disposition of the pipes which lead the water. 



&quot; And, in truth, the nerves of the machine which I am describing may 

 very well be compared to the pipes of these waterworks ; its muscles and 

 its tendons to the other various engines and springs which seem to move 

 them ; its animal spirits to the water which impels them, of which the 

 heait is the fountain ; while the cavities of the brain are the central 

 office. Moreover, respiration and other such actions as are natural and 

 usual in the body, and which depend on the course of the spirits, are like 

 the movements of a clock, or of a mill, which may be kept up by the 

 ordinary flow of the water. 



&quot;The external objects which, by their mere presence, act upon the organs 

 of the senses ; and, which, by this means, determine the corporal machine 

 to move in many different ways, according as the parts of the brain are 

 arranged, are like the strangers who, entering into some of the grottoes of 

 these waterworks, unconsciously cause the movements which take place 

 in their presence. For they cannot enter without treading upon certain 

 planks so arranged that, for example, if they approach a bathing Diana, 

 they cause her to hide among the reeds ; and if they attempt to follow her, 

 they see approaching a Neptune, who threatens them with his trident : or 

 if they try some other way, they cause some other monster who vomits 

 water into their faces, to dart out ; or like contrivances, according to the 

 fancy of the engineers who have made them. And lastly when the rational 

 soul is lodged in this machine, it will have its principal seat in the brain, 

 and will take the place of the engineer, who ought to be in that part of the 

 works with which all the pipes are connected, when he wishes to increase, 

 or to slacken, or in some way to alter their movements.&quot; l 



And again still more strongly : 



&quot; All the functions which I have attributed to this machine (the body), 

 as the digestion of food, the pulsation of the heart and of the arteries ; the 



1 &quot; Traite de 1 Homme &quot; (Cousin s Edition), p. 347. 



