672 THE AMERICAN NATURALIST [Vol. XLVI 



Navy, 4 = —.00036 



Ne. Plus Ultra, A = — .00615 

 White Flageolet, ^ = —.00196 



Discussion of such differences is obviously superfluous. 



IV. Recapitulation, Discussion and Tentative Con- 

 clusions 



The purpose of the series of investigations, described 

 in part, is to ascertain whether the depauperization 

 of the individual through the environmental com- 

 plexes constituting ''poor" agricultural conditions, in- 

 fluences the characteristics of its offspring, and if so, 

 how much. The problem of the chemical and physical 

 " causes" of the depauperization has received the most 

 intensive experimental consideration. The question of 

 the influence of the surroundings of the ascendants upon 

 the characteristics of the descendants has been much 

 more a matter of speculation. Yet the second of these 

 problems is of obvious importance to the agriculturist 

 and of interest to the evolutionist concerned with en- 

 vironmental factors. The time seems ripe, therefore, for 

 its consideration on the basis of extensive quantitative 

 experimental data. 



Notwithstanding the great progress which has been 

 made in the investigation of the relationship of the 

 chemical and physical properties of the substratum to 

 the characteristics of the plant, the diversity of results 

 and the clash of theories show that we have only entered 

 the edge of this field of research. In consideration of 

 these facts, and especially in view of the all but unsur- 

 mountable difficulties of controlling in large experiments 

 the conditions of growth of flowering plants, it has 

 seemed necessary in first studies to choose merely good 

 and bad growing conditions as indicated by yields in 

 actual cultures. Thus the methods are avowedly and in- 

 tentionally of the rough and ready sort. If in such ex- 

 periments an unquestionable influence of the conditions 



