PARTICULAR CASES 211 



But here again it is impossible to exclude the interpretation that 

 a variation in the direction of thickened solar epidermis might 

 have selection-value from very ancient days, to the arboreal 

 ape as well as to the bootless man. H. H. Wilder, in a paper 

 in which he gives a detailed comparison of the palms 

 and soles of Primates and Man {Anal. Anzeig. xiii. (1897), 

 pp. 250-6), distinctly refuses to commit himself to a Lamarckian 

 theory, believing that the facts may be equally well interpreted 

 in terms of variation and selection. 



Bollinger (1882) suggests that the weak development of the 

 breasts in women of the Dachauer district is due to the old- 

 established fashion of wearing tight corsets which are pressed 

 flat on the breasts. It is necessary to inquire {a) whether 

 the peculiarity is not a modification inflicted on each successive 

 generation, or whether it is ever exhibited by a Dachauer 

 woman who does not wear a corset ; and {b) whether the 

 same peculiarity does not occur where the fashion is entirely 

 different. 



Climatic Changes. — Virchow and others have laid stress on 

 the fact that many peculiarities in races of men and of other 

 living creatures are climatic in origin, and yet are now part of 

 the natural inheritance. But acclimatisation is usually a slow 

 and gradual process, involving selection of germinal variations, 

 and it is difficult to get clear-cut cases of climatic modifications. 

 It must also be remembered that Weismann expressly admits 

 that climatic influences, especially if long-continued, may 

 influence the germ-plasm along with whole system, and may 

 induce germinal variations that come to stay ; but this " has 

 certainly nothing to do with the view that functional modifica- 

 tions of any particular organ can cause a corresponding change 

 in the germ-plasm." (See The Germ-Plasm, 1893, p. 408.) 



In adjacent areas with different climatic and other environ- 

 mental conditions we not infrequently find closely related 

 species or local races. It seems impossible to doubt that these 



