262 EVOLUTION, OLD AND NEW. 



chiefly in man, who, as the most highly developed of 

 living beings, presents the problem in its most diffi- 

 cult and complicated aspect. If we had begun our 

 study with that of the lowest organisms, and had pro- 

 ceeded from these to the more complex ones, we should 

 have seen the progression which is observable in 

 organization, and the successive acquisition of various 

 special organs, with new faculties for every additional 

 organ. We should thus have seen that sense of needs — 

 originally hardly perceptible, but gradually increasing 

 in intensity and variety — ^has led to the attempt to 

 gratify them ; that the actions thus induced, having 

 become habitual and energetic, have occasioned the 

 development of organs adapted for their performance ; 

 that the force which excites organic movements can in 

 the case of the lowest animals exist outside them and 

 yet animate them; that this force was subsequently 

 introduced into the animals themselves, and fixed 

 within them ; and, lastly, that it gave rise to sensi- 

 bility and, in the end, to intelligence." * The reader 

 had better be on his guard here, and whenever Lamarck 

 is speculating about the lowest forms of action and 

 sensation. I have thought it weU, however, to give 

 enough of these speculations, as occasion arises, to show 

 their tendency. 



" Sensation is not the proximate cause of organic 

 movements. It may be so with the higher animals, 

 but it cannot be shown to be so with plants, nor even 

 with all known animals. At the outset of life there 

 was none of that sensation which could only arise 

 ' 'Phil. Zool.,' torn, i., edited by M. Martins, 1873, pp. 25, 26. 



