WEISMANN'S CONCESSIONS. 175 



WEISMANN'S CONCESSIONS. 



By LESTER F. WAKD. 



"VTEARLY three years ago, and before the appearance of the 

 -^^ second volume of Weismann's Essays,* in a Critique of 

 Weismann,t based entirely on statements contained in the first 

 volume, I intimated that in my judgment he had already ad- 

 mitted enough to invalidate his doctrine of the non-transmissi- 

 bility of acquired characters where these are of a functional na- 

 ture. After showing from his own language that, according to 

 his theory, no variation would be possible later than the Protozoan 

 stage of development, which was a reductio ad absurdum, I pro- 

 ceeded to point out that, apparently from a sense of this position, 

 he had actually admitted the possibility that external influences 

 may affect the germ. One of the passages embodying such an 

 admission is the following : 



" I believe, however, that they [hereditary variations] can be 

 referred to the various external influences to which the germ is 

 exposed before the commencement of embryonic development. 

 Hence we may fairly attribute to the adult organism influences 

 which determine the x^tiyletic development of its descendants. 

 For the germ cells are contained in the organism, and the ex- 

 ternal influences which affect them are intimately connected with 

 the state of the organism in which they lie hid. If it be well 

 nourished, the germ cells will have abundant nutriment ; and, 

 conversely, if it be weak and sickly, the germ cells will be arrested 

 in their growth. It is even possible that the effects of these influ- 

 ences may be more specialized ; that is to say, they may act only 

 upon certain parts of the germ cells." | 



In the same essay, speaking of the influence of climate, he also 

 uses language that has a decidedly Lamarckian sound : 



" It is difficult to say whether the changed climate may not 

 have first changed the germ, and if this were the case the accumu- 

 lation of effects through the action of heredity would present no 

 difficulty." * 



Upon this, my comment was : 



" I can not see why this is not conceding the whole issue. Of 



* Essays upon Heredity and Kindred Biological Prol^lems. By Dr. August Weis- 

 mann. Authorized Translation. Oxford: At the Clarendon Pre.ss. Vol. i, 1889; vol. 

 ii, 1892. 



f Neo Darwinism and Neo-Lamarckism. Annual Address of the President of the Bio- 

 logit-al Society of Washington, delivered January 24, 1891. Proceedings, vol. vi, Washing- 

 ton, 1891, pp. 45-5(1. 



X Essays, vol. i, pp. 103-104. # Ibid., p. 98. 



