548 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1918. 



the most careful upbringing, the individual never reaches the aver- 

 age developmental plane. Many children of this type die within a 

 few months of birth, not so much from actual disease as simply be- 

 cause they have not strength to live. Others survive, but are 

 physically, mentally, or morally deficient. Doubtless in some cases 

 there may be obscure faults in the environment, but there are very 

 many in which this is not so, and in which there are clear indications 

 of an innate defect of potentiality; in other words, of the fault being 

 in the seed and not in the soil. The great bulk of the mentally defi- 

 cient belongs to this group. 



The difference between these two types of so-called degeneracy, 

 however, lies not only in their mode of causation, but in their ulti- 

 mate results. That which is due to an inadequate or adverse environ- 

 ment acting upon the embryo — that is, after fertilization of the germ 

 cell has taken place — is, in most instances, an affection of the cells of 

 the body only. These are incapable of attaining their full develop- 

 ment, because some of the necessary external stimuli to that develop- 

 ment are lacking. If the want is supplied before the period of 

 growth is past, the arrears may be made up ; if not, some degree of 

 permanent defect results. In some cases it is probable that the germ 

 plasm which is stored within the individual, to give rise, in due time, 

 to another generation, may also be affected; but in most instances 

 this is not so. What is produced is a somatic modification only, the 

 germinal potentiality of the seed being unimpaired. The case is 

 entirely different with regard to that type of degeneracy which 

 appears in spite of a satisfactory environment. The defect here is 

 clearly germinal ; it is, in fact, a germ variation, and as such is trans- 

 missible to subsequent generations in accordance with the laws of 

 heredity. 



In view of this important and far-reaching difference between 

 these two types, usually comprehended by the word "degeneracy," 

 some verbal distinction is clearly necessary. In my opinion that term 

 should be restricted to the latter group, accordingly I venture to 

 define degeneracy as "a retrograde condition of the individual re- 

 sulting from a pathological variation of the germ cell"; and it is 

 in this sense that it will here be used. Perhaps the most convenient 

 word to denote the somatic modification arising from a defective 

 environment would be "decadency." 



Degeneracy, then, is the expression of a germ variation. It is 

 generally accepted by biologists that variations of the germ cell 

 tend to be transmitted to subsequent generations. It is doubtful 

 whether this transmission is invariable, and the laws governing it 

 are still very imperfectly known, but, as a broad fact, it is cer- 

 tainly true. It follows that the occurrence of variations is a phe- 

 nomenon of the utmost importance to the future of the race. Such 



