LAMARCK'S THEORY OF DESCENT 



347 



In explaining the second law he says : 



" The foundation of this law derives its proof from 

 the third, in which the facts known allow of no 

 doubt ; for, if the forces of action of an organ, by 

 their increase, further develop this organ — namely, 

 increase its size and power, as is constantly proved 

 by facts — we may be assured that the forces by which 

 it acts, just originated by a new want felt, would 

 necessarily give birth to the organ adapted to satisfy 

 this new want, if this organ had not before existed. 



" In truth, in animals so low as not to be able to 

 feel, it cannot be that we should attribute to a felt 

 want the formation of a new organ, this formation 

 being in such a case the product of a mechanical 

 cause, as that of a new movement produced in a part 

 of the fluids of the animal. 



" It is not the same in animals with a more compli- 

 cated structure, and which are able to feel. They 

 feel wants, and each want felt, exciting their inner 

 feeling, forthwith sets the fluids in motion and forces 

 them towards the point of the body where an action 

 may satisfy the want experienced. Now, if there 

 exists at this point an organ suitable for this action, 

 it is immediately cited to act ; and if the organ does 

 not exist, and only the felt want be for instance press- 

 ing and continuous, gradually the organ originates, 

 and is developed on account of the continuity and 

 energy of its employment. 



" If I had not been convinced : i, that the thought 

 alone of an action which strongly interests it suffices 

 to arouse the inner feeling of an individual ; 2, that a 

 felt want can itself arouse the feeling in question ; 

 3, that every emotion of inner feeling, resulting 

 from a want which is aroused, directs at the same 

 instant a mass of nervous fluid to the points to be set 

 in activity, that it also creates a flow thither of the 

 fluids of the body, and especially nutrient ones ; that, 

 finally, it then places in activity the organs already 



