254 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 
the whole value of that organism which determined its survival. 
This fact is continually disregarded by opponents of the neo-Darwinian 
position, yet this selection of the organism as a whole is the 
fundamental postulate from which the theory of selection starts. 
Thus it is not uncommom to read criticisms bearing on the early 
development of some organ, in which the inadequacy of selection is 
supposed to be proved by the writer demonstrating, or believing he 
has demonstrated, the fact that the particular variation in question 
must have been too small to be by itself of selection value. In many 
cases the particular variation would, no doubt, if taken alone be, as 
the objector asserts, too unimportant to be selected, but as it is the 
whole organism that is selected, it is not logical to make an artificial 
separation and study the development of one organ or structure 
irrespective of the other organs with which it is in nature associated. 
Every organ in its evolution must be considered in relation to the whole 
of the particular organism in which that particular stage of development 
of that organ is found. 
Starting, therefore, with this fact that the net value of adaptability 
of the whole organism to its environment must be the basis which 
determines selection or elimination, it will follow that certain lines of 
development will result from the application of this criterion. Ina 
series of organisms placed under new conditions, elimination will 
proceed along lines essential to bring about a proper adjustment to 
the new conditions. If the offspring of these adjusted organisms 
merely repeated in their generation the characters of the exterminated 
as well as of the surviving organisms, that temporary adjustment 
would be permanent as long as the conditions were unchanged. But 
since the offspring are produced only by the surviving organisms, 
selection is continually raised to higher and higher planes of adapta- 
tion, and, therefore, as long as conditions remain constant, the 
tendency of selection must be, as Darwin clearly saw, cumulative. 
He did not, however, apparently see that from this cumulative 
tendency definite variability must arise out of indefinite. 
Selection in direct relation to climatic conditions is, therefore, of 
very minor importance, while selection among the members of a 
species and all forms of inter-organismal selection is of infinitely more 
importance, since it is this interaction, produced by the offspring in 
different degrees inheriting the advantages of both parents (both of 
whom have survived on account of certain advantages), that leads to 
the cumulative development and never-ending struggle for survival. 
