ARTICLES ' 401 



disuse can be inherited. Indeed Weismann has gone further, 

 and has claimed to have produced evidence that these effects 

 cannot be inherited. 



This evidence is not a little extraordinary. If we turn to his 

 Essays on Heredity (English translation by Poulton, Schonland, 

 and Shipley) we read : " It can hardly be doubted that mutila- 

 tions are acquired characters . . . they are merely the reaction 

 of the body to external circumstances." He then proceeds to 

 recount how he cut the tails off a series of white mice, bred 

 from them, found that the young were born with tails, and 

 triumphantly concludes that he has proved that " acquired 

 characters " cannot be inherited. It seems incredible, but it 

 is, nevertheless, true that on the foundation of childish experi- 

 ments like these are based the confident assertions in many 

 textbooks (especially American), that Weismann had de- 

 molished the case for the inheritance of acquired characters. 

 Comment is superfluous ! 



During the last ten years, however, Kammerer, working 

 under Przibram in the Institute for Experimental Zoology in 

 Vienna, has carried out a series of experiments which, if con- 

 firmed, settles the question of the inheritability of acquired 

 characters for ever in the affirmative. Naturally his results 

 have aroused a storm of opposition, but his most keen sighted 

 opponents have seen clearly that the results are far too clear to 

 allow of the supposition of genuine mistakes in interpreting 

 the evidence. Either Kammerer has proved his point, or else 

 he is acting in scandalous bad faith, and this second alternative, 

 more or less concealed in diplomatic language, has been adopted 

 by many. 



The subjects of these experiments have been chiefly 

 Amphibia. A few of them may be briefly outlined here. There 

 exist in Europe two salamanders, one the yellow and black 

 form {Salamandra maculosa), which inhabits the lowlands, and 

 the other a black species {Salamandra aira), which lives at high 

 altitudes. Both are viviparous ; but S. maculosa gives rise to 

 30-40 gilled young, which live in water for six weeks before 

 losing their gills and metamorphosing into the land form. 

 S. atra, on the other hand, gives birth to only two young, which 

 are at birth land animals, and ready at once to take up the 

 parental mode of life. But if we cut open a pregnant black 

 salamander, we find inside her at least a dozen embryos. Of 

 these, however, only the two situated furthest back and nearest 

 the openings of the oviducts are destined to survive ; all the 

 rest in the course of development degenerate into a kind of 

 soup, which is devoured by the hindermost and serves to feed 

 them. These two lucky embryos have long gills, but these 

 gills are absorbed before birth. 



