Mat 27, 1910] 



SCIENCE 



817 



tinction of these two processes, a maze of 

 confused ideas, and he most obstinately con- 

 tinues to transfer the factor of selection, 

 which Darwin introduced for the first process, 

 and to apply it to the second process (specia- 

 tion). Of course, in the writings of Weis- 

 mann it is hard to quote a passage where he 

 does this clearly and unmistakably, since in 

 this respect clearness is altogether lacking, 

 but, in the present book, it is easily seen that 

 he actually intends to apply the principle of 

 selection to the formation of new species by 

 his reference to the mutation theory of de 

 Vries. Of course, de Vries makes the same 

 fundamental mistake. The mutation theory, 

 as should be evident to everybody, deals pre- 

 eminently and emphatically with the question 

 of speciation ; at any rate, de Vries claims that 

 it does, if he wants to explain the origin of 

 NEW species ty mutation, and consequently it 

 can not at all come into conflict with Dar- 

 win's principle of selection, which is intended 

 only as a factor in the transformation proc- 

 ess. Nevertheless, Weismann (as well as de 

 Vries) regards the mutation theory as op- 

 posed (" Einwurf," p. Y) to the selection 

 theory! Any one who expresses views like 

 these demonstrates only that the true Dar- 

 winian theory is not understood by him, and 

 that he has not the slightest idea of what the 

 meaning and significance of de Vries's ex- 

 periments are. As has been demonstrated 

 elsewhere,' de Vries himself did not under- 

 stand the bearing of his experiments upon the 

 evolution theory in general, and, consequently, 

 made the most serious mistakes in their in- 

 terpretation. 



This misunderstanding of Darwin's theory 

 explains why Weismann so stoutly maintains 

 that selection may create neiv things: he 

 needs some explanation for the origin of 

 new species. But this idea of his has been 

 criticized so often that he is forced to pay at 

 least some attention to the attacks, and, in- 

 deed, he admits that selection can not do any- 

 thing without the material, with which it 



'See Science, 23, May 11, 1906, p. 746; 24, 

 August 17, 1906, p. 214; 25, February 1, 1907, 

 p. 185. 



is to work, being furnished by variation: a 

 number of writers have called his attention 

 to this, and have reminded him that, if this 

 is so, it is not logical to say that natural se- 

 lection, by killing the unfit variations, '' cre- 

 ates " new ones, but that the word " pre- 

 serves " should be used. This objection is 

 absolutely well founded, as everybody will 

 grant, and Weismann has been cornered by 

 it so completely, that no other escape remains 

 for him but to say that this objection is 

 "nonsensical" (sinnlos, p. 81). Further 

 comment is unnecessary. 



In his treatment of the " Lamarckian prin- 

 ciple " and the causes of variation, Weismann 

 shows the same lack of understanding, or, if 

 not, a rather vicious tendency to distort facts 

 and ideas. The Lamarckian principle, in its 

 widest sense, which is also accepted by Dar- 

 win, says that the variations which are trans- 

 mitted to the offspring are caused by the en- 

 vironment. It is true, Lamarck himself dis- 

 cussed "chiefly" (hauptsaechlich) use and 

 non-use of parts as cause of variation. But 

 Weismann admits, by using the word 

 " chiefly," that there are others, and he surely 

 ought to know that Darwin and subsequent 

 writers have enlarged this principle so as to 

 regard all reactions of the body to environ- 

 mental factors as variations in this sense (ac- 

 quired characters). In the present booklet, 

 however, Weismann restricts the Lamarckian 

 principle strictly to " use and non-use," and 

 then, of course, it is easy for him to show that 

 in particular cases quoted by him the La- 

 marckian principle does not apply.' 



His chief argument against the Lamarck- 

 ian principle is that we are to entertain 

 " strong doubts " (p. 6) against the coopera- 

 tion of this principle, and that the trans- 

 mission of acquired characters is " hard to 



' This is a beautiful illustration of Weis- 

 m-annian logic. On page 6, line 10, he uses the 

 word "chiefly" (hauptsaechlich) in this connec- 

 tion, while almost immediately below, on the bot- 

 tom line of the same page, " functional " varia- 

 tions (by use and non-use) become the " only 

 ones" (allein), which constitute the Lamarckian 

 principle. This surely justifies what we have said 

 above on his tendency to distort things. 



