( cvi ) 



ment of his views on evolution in 1802, the celebiatecl 

 "Philosophic Zoologique " was not published until 1809, 

 fifteen years after the appearance of the "Zoonomia," and it 

 is vincertain whether the author of the later work had ever 

 seen the earlier treatise. Pi'ofessor Osborn concludes upon 

 the whole that he had not (J. c, pp. 152 — 155). However this 

 may be, the technical use of the words " acquired characters " 

 is chiefly due to his memoir. The essential passnges are 

 the two following Laws of Lamarck : — - 



'■'■ Preitiiere Loi. — Dans tout auimal qui n'a point depasse le 

 terme de ces developpements, I'emploi plus frequent et soutenu 

 d'un organe quelconque, fortifie pen a pen cet organe, le de- 

 veloppe, I'aggrandit, et luidonne une puis.'sance proportionnee a 

 la duree de cet emploi ; tandis que le defaut constant d'usage 

 de tel organe, I'affaiblit insensiblement, le deteriore, diminue 

 progressivement ces facultes, et finit par le faire disparaitre." 



" Deuxieme Loi. — Tout ce que la nature a fait acquerir ou 

 perdre aux individus par I'influence des circonstances oii leur 

 race se trouve depuis longtemps 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 chanyements acquis soient communs aux deux 

 sexes ou a ceux qui ont produit ces nouveaux individus." * 



Opposite to the characters which Lamarck spoke of as 

 " acquired " are the characters which may be called con- 

 stitutional, congenital, geiietic, inborn, innate or inherent. Other 

 names have been specially proposed in order to render a])parent 

 the distinction between these two classes of chai-acters. 

 Weismann employed terms which set forth their different 

 origin. The inherent he called blastogenic, expressing an origin 

 that lay far back in germ-cell from which the individual arose. 

 Acquired characters he called somatogenic, to expi-ess a later 

 origin due to circumstances which had aftected the body-cells. 



* "Philosophic Zoologique," tome i. p. 235, l^^dition Savy, 1873: 

 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 jirotest 

 against the restricted appKcation 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 

 assum2:)tion. 



