260 PRKSIDENt's address. — SE( TION D. 



Plants " (■• Darwin and Modern Science," 1910 — the Darwin Centenary 

 Volume). He refers to the fact that cereals cultivated in a northern 

 climate produce individuals which ripen their seeds early in southern 

 countries. The authority is Schiibler. In Cieslar's experiments, seeds 

 of conifers from the Alps, when planted in the plains, produced plants 

 of slow growth and small diameter. 



Bordage (quoted by Doad}^ in " Outlines of Evolutionary Biology," 

 1912) found that peach trees in the Island of Reunion have responded 

 to their environment by becoming practically evergreen. Seedlings 

 of the trees so modified retain their modification when grown in 

 climates in which the peach is usually deciduous. 



It is very interesting to note that a somatic change may be heritable 

 at first, but the effect of the stimulus that has produced it may fail to 

 persist. Klebs [loc. sit.) produced an artificially modified inflorescence 

 in Veronica chamsedrys. From seeds from this inflorescence some plants 

 that exhibited twisting were produced. These did not behave as did 

 the twisted Dipsacus isolated by De Vries, which each year produced 

 twisted individuals in a definite percentage. Klebs found that, in 

 vegetative propagation, the twisting began to disappear in the second 

 generation, that the process v/as hasteiied in the third, and that finally 

 disappearance was complete. In seedlings it disappeared much more 

 quicklv. 



By cultivation in moist air and removal of foliage leaves, the same 

 species of Veronica was induced to transform its inflorescence to foliage 

 shoots. In seven-tenths of the plants obtained from the transformed 

 shoots the modification appeared in the following year. During some 

 years there has been gradual diminution of the modification in plants 

 obtamed by vegetative propagatioii or as -seedlings. 



Rats and mice reared in abnormal conditions as to temperature 

 were fouiid by Sumner to exhibit definite modifications in the mean 

 length of the tail, foot, and ear, and these modifications proved 

 heritable by offspring reared in nt)rmal conditions. This experiment 

 differs from those of Tower, for the parents became modified in 

 Sumner's experiments, not merely the germ plasm. 



It is in this connexion worthy of note that mice inhabiting caverns 

 achieve certain somatic modifications — the ears become large, the 

 whiskers greatly developed, and the eyes prominent (Banta, loc. cit., 

 p. 20, and other authorities quoted there). It would be of interest 

 to know whether the offspring of these animals reared in normal condi- 

 tions would present the same variations. 



The exposed roots of many epipliytic plants become flattened and 

 develop chlorophyll. It is not questioned that this modification takes 

 place as an adaptation under the influence of light. Goebel (" Organo- 

 graphy," II, 2S5) refers to the case of Phalaenopsis Schilleriana in which 

 it was found that a portion several centimetres long of a root from 



