SCIENCE 



[N. S. Vol. XXXIII. No. 838 



alpine characters enumerated are dis- 

 played at once as a direct somatic re- 

 sponse. "When seeds are taken from plants 

 on the elevated plateau where their ances- 

 tors may have been for many years or 

 many centuries (perhaps as long as 2,000 

 years) and sowed at Vienna, and at other 

 places, it was found that in four genera- 

 tions the leaves lost their xerophytic forms 

 and structure, but the other characters 

 were retained within the limits of varia- 

 bility. The stems showed an increase in 

 average length of 1 to 2 cm., the roots 

 changed as much, but the reproductive 

 branches and floral organs retained their 

 alpine characters. The slight modifications 

 undergone by these features were seen to 

 reach a maximum and to decrease in the 

 latest generations cultivated. The struc- 

 tural changes and implied functional 

 changes are originally direct somatic re- 

 sponses; there is no escape from the con- 

 clusions that the impress of the alpine 

 climate on the soma has been communi- 

 cated to the germ-plasm in such a manner 

 as to be transmissible, and the suggestion 

 lies near that repeated and continued ex- 

 citation by climatic factors may have been 

 the essential factor in such fixation. 



A related phase of the sub.ject is that of 

 the interposition of environic factors in 

 mutations and hybridizations. De Vries 

 appears to have first called attention to the 

 fact that the composition of hybrid 

 progenies of mutants with each other and 

 with the parental form might be altered by 

 nutritive conditions, and the author has de- 

 scribed mutants given off by CEnothera 

 LamarcMana in New York which had 

 never been seen in Amsterdam. Further- 

 more, in discussing the divergent results of 

 De Vries and myself, obtained by crossing 

 the same forms in Amsterdam and New 

 York, the suggestion was made in 1905, 

 that "the manner in which the various 



qualities in the two parents are grouped in 

 the progeny might be capable of a wide 

 range of variation. Many indications lead 

 to the suggestion that the dominancy and 

 prevalency, latency and recessivity of any 

 character may be more or less influenced by 

 the conditions attendant upon the hybridi- 

 zation; the operative factors might include 

 individual qualities as well as external 

 conditions. ' ' 



Much more striking evidence upon the 

 matter has been recently obtained by 

 Tower in intercrossing Leptinotarsa de- 

 cemlineata, L. multilineata, L. oblongata 

 and other species in their habitats in 

 southern Mexico, and at the Desert Lab- 

 oratory. The observations were carried on 

 with both normal and hybrid crosses, in 

 crosses between races which had been 

 built up selectively, and between forms 

 which arose as sports proving conclusively 

 that external agencies may alter the action 

 of paired reproductive elements. Kam- 

 merer's contribution to this subject con- 

 sisted in demonstrating that newly induced 

 color characters in Lacerta displayed dom- 

 inances different from those of the orig- 

 inal types, while Tennent has proved that 

 the dominances in crosses of Hipponoe and 

 Toxopneustes variously attributed to sea- 

 sonal changes, variations in temperature, 

 etc., are in reality to be attributed to the 

 concentration of the OH ions in the sea- 

 water. 



The flrst realization of results of im- 

 portance from cultures widely extended 

 geographically have been obtained in the 

 experiments with LeptinotarsiE by Tower, 

 in which various species of these beetles 

 were studied in their habitats in southern 

 Mexico, in open air and glass houses as far 

 north as Chicago, as far east as the At- 

 lantic and as far west as the Desert Lab- 

 oratory. Facilities for work upon special 

 problems are now being organized at sev- 



