14 Cuvier's Biographical Monoir ofM. de Lamarck. 



the same waj' that his researches on the principal facts of phy- 

 sics contained a chemistry of that character. In his opinion, 

 the egg contains nothing prepared for Hfe before being fecun- 

 dated, and the embryo of the chick becomes susceptible of vital 

 motion only by the action of the seminal vapour : but, if we ad- 

 mit that there exists in the universe a fluid analogous to this 

 vapour, and capable of acting upon matter placed in favourable 

 circumstances, as in the case of the embryon, which it organizes 

 and fits for the enjoyment of Hfe, we will then be able to form 

 an idea of spontaneous generations. Heat alone is perhaps the 

 agent employed by Nature to produce these incipient organiza- 

 tions ; or it may act in concert with electricity. M. de Lamarck 

 did not believe that a bird, a horse, nor even an insect, could 

 directly form themselves in this manner ; but, in regard to the 

 most simple living bodies, such as occupy the extremity of the 

 scale in the different kingdoms, he perceived no difficulty ; for 

 a monad or a polypus are, in his opinion, a thousand times 

 more easily formed than the embryo of a chick. But how do 

 beings of more complicated structure, such as spontaneous ge- 

 neration could never produce, derive their existence ? Nothing, 

 according to him, is more easy to be conceived. If the orgasm, 

 excited by this organizing fluid, be prolonged, it will augment 

 the consistency of the containing parts, and render them suscep- 

 tible of re-acting on the moving fluids which they contain, and 

 an irritability will be produced, which will consequently be pos- 

 sessed of feeling. The first efforts of a being thus beginning to 

 develope itself must tend to procure it the means of subsistence, 

 and to form for itself a nutritive organ. Hence the existence of 

 an alimentary canal ! Other wants and desires, produced by cir- 

 cumstances, will lead to other efforts, which will produce other 

 organs : for, according to a hypothesis inseparable from the rest, 

 it is not the organs, that is to say, the nature and the form of 

 the parts, which give rise to habits and faculties ; but it is the 

 latter which in process of time give birth to the organs. It is 

 the desire and the attempt to swim that produces membranes in 

 the feet of aquatic birds ; wading in the water, and at the same 

 time the desire to avoid wet, has lengthened the legs of such as 

 frequent the sides of river,s ; and it is the desire of flying that 

 has converted the arms of all birds into wings, «nd their hairs 



