254 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



[Vol. 2 



work on which now concepts in biological science may be for- 

 mulated. The group of problems with which we are endeavor- 

 ing to make headway are in the domain of physiology and 

 their solution may be reached only by experimentation, the re- 

 sults of which are to be interpreted in terms of physico-chem- 

 ical activities and their correlated functional manifestations 

 in the living organism. 



That phylogenetic advance in the main lines of descent in 

 the plant kingdom at least reflects, or harmonizes with, the ex- 

 pectancies of somatic experience is tacitly admitted on all 

 hands, but that the direct response of a shoot to the environ- 

 ment, or conversely stated, that the impression on the soma 

 made by environic agencies is communicated to successive gen- 

 erations in a constant manner has not been demonstrated, 

 although it seems fairly established that certain experiences 

 of individual plants are reflected directly or indirectly to the 

 next generation, and in lesser degree to the next or second 

 generation. How are lasting or permanent changes brought 

 about? 



Functional adequacy and architectural suitability present 

 themselves on every hand, yet about all of our reliable evi- 

 dence is against anything like a direct or functional adaptation 

 becoming hereditary or continuously transmissible. 



Two methods of experimental attack on the problem are 

 available. Species showing measurable features and of sim- 

 ple genetic constitution may be taken from their habitual or 

 known environment to other localities in which the climatic 

 and soil characters may be calibrated and the response of the 

 organism, somatically and hereditarily, determined. Hun- 

 dreds of thousands of introductions and acclimatization opera- 

 tions have been carried out in agriculture, horticulture, and 

 especially in botanic gardens during the last century, yet 

 neither the genetic constitution nor the response of the or- 



ganism has been followed by trained observers who compared 

 the plants in their different habitats. The exposure of the 

 organism to any climatic complex, of course, might affect the 

 germ-plasm directly, and any departure detected in such ex- 

 perimentation must be evaluated by controlled cultures under 



