MODIFICATIONS 519 



social organisation provides a means an external heritage 

 whereby the results of modifications may be practically 

 though not organically entailed. To this elementary distinction 

 necessary, however, for clear thinking we must repeatedly 

 refer. 



By a " social variation " we mean a change in the organisation 

 of a societary form, and it is not within the scope of this chapter 

 to discuss its nature and origin. That is part of the task of the 

 sociologist ; and its accomplishment lies far ahead. It may 

 not be presumptuous, however, to make this suggestion. A 

 variation expressing itself in an individual organism is marked 

 by changes in many individual units, and these changes have 

 to be described and measured. But the origin of the variation 

 was germinal, in the " immortal " germ-plasm which gives 

 continuity to the chain of transient generations. Thus we are 

 led to think that those social changes that really count must 

 have their basis in that which is to societary forms what the 

 germ-plasm is to generations of organisms, the esprit de corps 

 (in the unrealisable full meaning of the phrase !) which gives 

 unity to every societary form whether it be big or little. 



Modifications. Besides " variations " in the strict sense, 

 there are other organic changes, technically known as " modifi- 

 cations," or, more awkwardly, as " acquired characters." They 

 are definable as bodily structural changes acquired by the 

 individual organism as the direct result of changes in function 

 (use or disuse) or of changes in the environment, and so tran- 

 scending the limits of organic elasticity that they may persist 

 after the inducing conditions have ceased to operate. They 

 are exogenous, somatogenic changes, as contrasted with endo- 

 genous, blastogenic changes. They are the direct results of 

 peculiarities in " nurture," as contrasted with inborn changes 

 in the inherited " nature," to use the convenient words with 

 which Mr. Galton, following Shakespeare, has made us familiar. 

 That they are, after all, reactions of the inherited nature to 



