DEGENERACY TREDGOLD. 561 



become insane. The ascertainment of the number of offspring who 

 are hereditarily affected thus becomes a matter of the greatest diffi- 

 culty, and yet this is essential in order to prove that the transmission 

 is in accordance with Mendelism. My own experience is that, while 

 all the offspring of two markedly degenerate persons are always 

 defective, the children resulting from the union of a pronounced 

 degenerate with a healthy individual tend to be, not some normal 

 and some abnormal, but all of them of abnormal constitution. If 

 one parent only bears the taint in slight degree, it is not uncommon 

 to find some children affected while others entirely escape ; but even 

 here it is by no means rare for all the children to evince a distinct 

 psychopathic failing. Whilst, therefore, it is hazardous to dogmatize 

 on the subject — for the facts are by no means conclusive — the avail- 

 able evidence seems to suggest that the inheritance is more often of 

 the blended than of the Mendelian type. 



I have spoken of the pronounced grades of mental defect as being 

 the culmination of degeneracy ; but it is not always thus cumulative, 

 and it is possible that the mating of a person suffering from a milder 

 degree of germinal impairment with healthy stock might, after a 

 few generations, lead to the eradication of the impairment and so to 

 regeneracy. But the experiment would be somewhat hazardous for 

 the individual offspring. Severe exciting factors might readily fan 

 the slumbering spark into a violent flame; and this is probably the 

 explanation of many so-called sporadic cases of insanity and even of 

 mental deficiency. Such exciting factors may be supplied by injury 

 during birth, infectious disease during childhood, excess or strain 

 during adolescence or maturity, or indeed any untoward condition 

 of the environment, whether of intra- or extra-uterine life. And, 

 should the germinal impairment be still more pronounced, it seems 

 highly probable not only that mating with healthy stock is power- 

 less to neutralise the defect, but that there is the greatest danger of 

 a considerable reduction of the mental vigor and durability of 

 all the offspring and consequently of a marked decline in the net 

 capacity of the community. It is by such means that I conceive 

 that a nation, while still surviving, may not only lose its power to 

 advance, but may be rendered incapable of successful competition 

 against its more vigorous neighbors and so sink to a lower plane. 

 And when we take into account the neutralization of the force of 

 natural selection which occurs in a civilized as opposed to a more 

 barbarous community, and which prevents the elimination of these 

 unsound members, it is not difficult to understand how it has come 

 about that nations which have reached a high degree of civilization 

 should in course of time have been overrun by a horde of barbarians. 

 For with nations, as with individuals, it is the " fit" who survive. 



