THE Ly\WS OF LAMARCK 141 



produced by their own exertions, in response to pleasures 

 and pains, and many of these acquired forms or propensities 

 are transmitted to their posterity.'^ Although Lamarck 

 made a preliminary statement of his views on evolution 

 in 1802, the celebrated Philosophie Zoologique was not 

 published until 1809, fifteen years after the appearance of 

 Darwin's Zoonomia, and it is uncertain whether the author 

 of the later work had ever seen the earlier treatise. 

 Professor Osborn concludes upon the whole that he had 

 not (1. c, pp. I 52-5), However this may be, the technical 

 use of the words ' acquired characters ' is chiefly due to 

 his memoir. The essential passages are the two following- 

 Laws of Lamarck : — • 



' Premiere Loi. — Dans tout animal qui n'a point depasse 

 le terme de ses developpemens, I'emploi plus frequent 

 et soutenu d'un organe quelconque, fortifie peu a peu 

 cet organe, le developpe, I'agrandit, et lui donne une 

 puissance proportionnee a la duree de cet emploi ; tandis 

 que le defaut constant d'usage de tel organe, Taffoiblit 

 insensiblement, le deteriore, diminue progressivement 

 ses facultes, et finit par le faire disparoitre.' 



' Deuxieme Lot. — Tout ce que la nature a fait acqtidrir 

 ou perdre aux individus par I'influence des circonstances 

 ou leur race se trouve depuis long-temps exposee, et, par 

 consequent, par I'influence de I'emploi predominant de tel 

 organe, ou par celle d'un defaut constant d'usage de telle 

 partie ; elle le conserve par la generation aux nouveaux 

 individus qui en proviennent, pourvu que les changemens 

 acqtiis soient communs aux deux sexes, ou a ceux qui ont 

 produit ces nouveaux individus.' ^ 



Opposite to the characters which Lamarck spoke of as 

 ' acqtcired ' are the characters which may be called C07i- 

 stittitional, congenita U genetic, inborn, innate or inherent, 



' Zoonomia, 1794. Quoted by Professor H. F. Osborn, Fro?ti the 

 Greeks to Darwin. New York, 1894, p. 145. 



'^ Philosophie Zoologique, tome i. p. 235, Nouv. iSd., 1830 : quoted by 

 Professor E. R. Lankester in Nature, vol. xli. 1890, p. 415. There 

 had been a tendency in the discussion on this subject to protest against 

 the restricted appHcation of the word ' acquired ', and it was assumed that 

 the use was quite recent, and in fact due to Professor Weismann himself. 

 Professor Lankester shows the error of this assumption. 



