LAMARCK'S THEORY OF DESCENT 



337 



act of intelligence. None of these can indeed freely 

 vary its actions; none of them has the power of 

 abandoning what we call its industry to adopt any 

 other kind. 



" There is, then, nothing wonderful in the supposed 

 industry of the ant-lion {Myrmeleon formica-leo), 

 which, having thrown up a hillock of movable sand, 

 waits until its booty is thrown down to the bottom 

 of its funnel by the showers of sand to become its 

 victim ; also there is none in the manoeuvre of the 

 oyster, which, to satisfy all its wants, does nothing but 

 open and close its shell. So long as their organiza- 

 tion is not changed they will always, both of them, 

 do what we see them do, and they will do it neither 

 voluntarily nor rationally. 



" This is not the case with the vertebrate animals, 

 and it is among them, especially in the birds and 

 mammals, that we observe in their actions traces of a 

 true industry ; because in difficult cases their intelli- 

 gence, in spite of their propensity to habits, can aid 

 them in varying their actions. These acts, however, 

 are not common, and are only slightly manifested in 

 certain races which have exercised them more, as we 

 have had frequent occasion to remark." 



Lamarck then (chapter vi.) examines into the nature 

 of the will, which he says is really the principle under- 

 lying all the actions of animals. The will, he says, is 

 one of the results of thought, the result of a reflux of 

 a portion of the nervous fluid towards the parts which 

 are to act. 



He compares the brain to a register on which are 

 imprinted ideas of all kinds acquired by the individual, 

 so that this individual provokes at will an effusion of 

 the nervous fluid on this register, and directs it to any 

 particular page. The remainder of the second volume 



