62 THE TREND OF THE RACE 
stances to fall victims to insanity. Not improbably the very 
large number of cases in which the mating of normal and 
feeble-minded produce children of the latter class are due not so 
much to the heterozygous character of the putative normals as to 
partial blending, or irregular and incomplete dominance. As our 
previous discussion has shown, where one parent is feeble-minded 
or insane, and the other normal, it is quite exceptional for all the 
children to be free from the mental taint of the afflicted parent. 
SYPHILIS AND MENTAL DEFECT 
The réle of syphilis in the causation of feeble-mindedness, 
epilepsy, and other forms of mental defect is still uncertain, 
despite a considerable amount of investigation devoted to the 
subject. Formerly syphilis was not considered to be accountable 
for a large percentage of mental defect, because only a small 
proportion of defectives were found to manifest any obvious signs 
of the disease. Since the discovery of the Wassermann and other 
tests it has been possible to detect syphilitic infection in numerous 
cases in which the disease was not revealed by any external 
symptoms. The Wassermann test, however, is apt to give very 
different results according to the particular way in which it is 
carried out. It is agreed that the absence of the positive Wasser- 
mann does not necessarily indicate the absence of syphilis, but a 
positive test except in the presence of a few other diseases or 
unusual conditions is held to constitute a strong proof that 
syphilis is present. Applications of the Wassermann tests to 
mental defectives have yielded surprisingly discrepant results. 
Goddard, in his work on feeble-mindedness, states that less than 
I per cent show syphilitic infection. Thomson, Boas, Hjort 
and Leschly in studying 2,061 mental defectives found that only 
1.5 per cent gave a positive Wassermann reaction. Lippmann 
found 9 per cent of positive reactions in one asylum, and 13 per 
cent in another. Dean found that out of 330 idiots of various 
ages in Potsdam 15 per cent were syphilitic. Krober obtained 
positive results in 21.4 per cent of 262 idiots.? 
1 Reference may also be made to the work of Atwood and Brofenbrenner who by 
