TJie InJieritance of Acquired Characters 29 



by Capsella can better be explained by the gradual natu- 

 ral selection of just those gemiinal variations that best 

 fitted individuals to cope with alpine conditions. This 

 would result in the gradual establishment of a strain 

 of germ plasm that would produce body structures fitted 

 to alpine conditions. In other words, this is just the 

 way in which natural selection would develop a new 

 elementary species from the original t}pe. If such a 

 type were established, of course its gcnn phism would 

 produce alpine plants, even under lowland conditions. 

 They might not survive long, and natural selection might 

 eliminate them, but their structure would be due, not to 

 the inheritance of somatic structures, but to the inherit- 

 ance of an alpine germ plasm. 



The objection to Zedebaur's conclusions on the 

 grounds that the result may be attributed to natural 

 selection has been avoided by the famous experiments 

 of Bonnier (5). In 1884, this investigator began mak- 

 ing plantations in the lowlands and at various altitudes 

 in the Alps, so arranged that the two individuals to be 

 compared were produced by dividing one plant. After 

 a lapse of over thirty years he has made the following 

 report. A few of the plants taken from the plains to 

 alpine stations died, but a list is given of fifty-eight species 

 that proved able to maintain themselves at high altitude. 

 These have all undergone changes which make them 

 closely resemble indigenous alpine plants.' In at least 



^ The principal chan<::cs arc relatively lari^a- (levelo|)ment of tiie 

 subterranean as compared with aerial parts, shorteninj^ of the leaves and 

 of the internodes of stems, increased hairiness, and relatively larger 

 development of bark and protective tissues. The leaves become thicker 

 in proportion to their surface and are a deeper green, with more higlily 

 developed palisade tissue and a larger numlx'r of ihloroplasts, while 

 the flowers are larger and more highl}'^ colored. 



