No. 529] 



ORGANIC RESPONSE 



39 



Many of the purely accommodative adjustments dis- 

 played by these organisms and by Paramcecia as well as 

 the extremes of variability induced by external agencies 

 and continued by selection, do not become fixed and are 

 not transmissible even in a series of generations by fis- 

 sion. The recent work of Pringsheim, however, shows 

 that some alterations in the way of accommodations or 

 functional responses of yeasts and bacteria to unusual 

 temperatures, culture media, and toxic substances become 

 fixed and transmissible both by fission and through 

 spores. It is not clear, however, that the differential 

 action of the exciting agent upon soma and germ can be 

 made out, and perhaps nothing more definite might be 

 said than that both are directly and simultaneously ex- 

 posed and exhibit coincident reaction. 



When we pass to a consideration of the results of Zed- 

 erbauer and Klebs, however, the evidence becomes much 

 more decisive. A ( 'apse/la was found growing at an ele- 

 vation of 2,000 to 2,400 meters in Asia Minor which had 

 hairy stems, 2-4 cm. long xerophytic leaves, and reddish 

 flowers. This plant had been evidently introduced from 

 the lowlands by man along a route that has been in use 

 for more than 2,000 years. The Capsvllu of the lower 

 plains forms a stem 30-40 cm. high, lias whitish flowers 

 and broad leaves ; when its seeds are taken to elevations 

 with climates comparable to the above, individuals are 

 developed duplicating those of the highlands, so that the 

 characteristic features of this alpine form are clearly 

 direct somatic reactions; and that they have become 

 fixed and fully transmissible is demonstrated by the fact 

 that in a series of generations grown at lower levels the 

 stem characters, as well as those of the reproductive 

 branches and floral organs, retained their alpine acquired 

 characters, although the leaves, as might be expected, 

 returned to a mesophytic form with broad lamina?. 



The results obtained by Klebs include divergences of 

 stem habit, number and structure of floral organs in 

 Sempervivum which are not capable of being interpreted 

 as functional or adaptive responses to the agencies which 

 called them out and were found to be fully transmissible 



