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LAMARCK, HIS LIFE AND WORK 



" I have already made it evident that this internal 

 force which produces movements and actions should 

 derive its origin in the intimate feeling of existence 

 which animals with a nervous system possess, and 

 that this feeling, solicited or aroused by needs, should 

 then start into motion the subtile fluid contained in 

 the nerves and carry it to the muscles which should 

 act, this producing the actions which the needs 

 require. 



" Moreover, every want felt produces an emotion 

 in the inner feeling of the individual which ex- 

 periences it ; and from this emotion of the feeling 

 in question arises the force which gives origin to 

 the movement of the parts which are placed in ac- 

 tivity. . . . 



" Thus, in the animals which possess the power of 

 acting — namely, the force productive of movements 

 and actions — the inner feeling, which on each oc- 

 casion originates this force, being excited by some 

 need, places in action the power or force in question ; 

 excites the movement of displacement in the subtile 

 fluid of the nerves — which the ancients called animal 

 spirits; directs this fluid towards that of its organs 

 which any want impels to action ; finally makes this 

 same fluid flow back into its habitual reservoirs when 

 the needs no longer require the organ to act. 



"The inner feeling takes the place of the will; 

 for it is now important to consider that every 

 animal which does not possess the special organ 

 in which or by which it executes thoughts, judg- 

 ments, etc., has in reality no will, does not make a 

 choice, and consequently cannot control the move- 

 ments which its inner feeling excites. Instinct directs 

 these actions, and we shall see that this direction al- 

 ways results from emotions of the inner feeling, in 

 which intelligence has no part, and from the organ- 

 ization even which the habits have modified, in such 

 a manner that the needs of animals which are in this 



