1080 KEPORT OF COMMISSIONER OF FISH AND FISHERIES. [100] 



Fourth law : "All of that which has been acquired, outliued, or changed 

 in the organization of individuals in the course of their lives is preserved 

 and transmitted by the process of reproduction to the offspring which 

 came from such parentage as had experienced such alterations." This 

 law recognizes the influence of heredity. 



The influence of the use or disuse of parts is stated in effect as follows 

 by Lamarck in Aninmux sans Vertebres, I, p. 60, and also in his Philoso- 

 phie zoologique (1809) : 



"Want of use of an organ, arising from acquired habits, gradually 

 impoverishes an organ, and ends in causing it to disappear. 



"The frequent use of an organ, arising constantly from such habits, 

 augments its faculties or capabilities, causing it to acquire dimensions 

 and a power of action which it does not have in animals exercising it 

 less." 



He also speaks of penchants, or impulses arising from the sentiment in- 

 terieur {An. sans Vert. I, 81), where he speaks of the efforts made by 

 animals for their self-preservation, where the principle of the struggle 

 for existence seems to be dimly, and perhaps tacitly, recognized. He 

 alludes to the manifestation by animals of such impulses as these: " To 

 fly from pain ; to seek and seize their nourishment; to perform the 

 sexual act when their organizations solicit them; to seek for pleasant 

 places and prepare for themselves means favorable for their conserva- 

 tion; to withdraw from painful conditions and everything which con- 

 strains or incommodes them ; to seek for pleasant, advantageous situa- 

 tions, shelter and the sun's heat during cold periods, shade and cool 

 places during the hot season ; to satisfy the need of nourishing them- 

 selves, sometimes with voracity, either from the pleasure they find 

 therein or the unrest which arises from the want of food ; to give them- 

 selves up to the enjoyment of the sexual act, or to ardently seek 

 occasion for it when their needs ))rovoke or solicit it ; to take repose 

 and sleep, when their other needs are satisfied." 



Intelligent impulses he speaks of as impelling an animal "to chase 

 its prey, to watch it with patience, to lay snares ; to employ new and 

 various means, according to circumstances, to satisfy each of its ne^ls ; 

 to resort to poltroonery or cowardice when weak in consequence of an 

 excessive fear of danger ; to preserve itself from danger by means of 

 various ruses." 



Selfish impulses {An. sans Vert. I, p. 82) are spoken of as impelling 

 an animal "to escape becoming the prey of others if the latter are 

 stronger; to chase and combat other animals which approach its 

 female, or such that covet her jjossession." In this last observation 

 he recognizes the struggle for possession amongst rival males, but does 

 not recognize the principle of sexual selection. 



Finally, he says animals are impelled " to prefer above all else that 

 which they can do to procure for themselves the enjoyment of some ad- 

 vantage." 



