22 THE DOCTRINE OF DESCENT. 



citation dwindle into the scarce perceptible motions of 

 the simplest protoplasmic animalculae, it is evident that 

 there can be no question here of either consciousness or 

 will. We cannot then separate the idea of those sensa- 

 tions of desire and aversion, by which motions are ex- 

 cited, from the elementary attributes of matter, as we are 

 wont to do with regard to the higher animals.^ 



In precisely the same sense, it was said some years 

 ago by one of the most talented investigators of lan- 

 guage — Lazarus Geiger, now unfortunately deceased : " 

 " But how is it, if further down, below the world of 

 nerves, a sensation should exist which we are not capa- 

 ble of understanding? And it probably must be so. 

 For as a body that we feel could not exist unless it con- 

 sisted of atoms that we do not feel, and as we could not 

 see a motion were it not accompanied by waves of light 

 which we do not see, neither could a complex living being 

 experience a sensation strong enough for us to feel it 

 also, in consequence of the motion by which it is mani- 

 fested, if something similar, though far weaker and im- 

 perceptible to us, did not occur in the elements, that is 

 to say, in the atoms. If we only consider that we are as 

 little capable of knowing that the falling stone feels noth- 

 ing, as that it does feel; it is fully open to us to decide, 

 in accordance with the greatest probability, that the world 

 is susceptible of explanation." 



We have examined the limits which the investigation 

 of nature has prescribed for itself. The organic world, 

 far from rearing itself before us as an incomprehensible 

 entity, invites us to fathom its nature, and promises to 

 reflect fresh light upon the inanimate world. 



We must now pass in review a great portion of ani- 



