246 A STUDY OF HEREDITY IN INSANITY [Oct. 



only in 17 were both mates neuropathic, in 93 one mate was neuro- 

 pathic and the other normal, and in 62 both mates were normal. 



Our material affords a means of estimating the probable pro- 

 portion of individuals, in the communities in which our study was 

 made, who carry the neuropathic taint. 



It will be borne in mind that an individual who is normal but 

 who carries the neuropathic taint and is capable of transmitting 

 it, can have neuropathic offspring only when his mate is either 

 neuropathic or normal but, like himself, carries the taint ; for if 

 his mate is normal and of pure normal ancestry no neuropathic 

 offspring will result, as has already been shown, and as is illus- 

 trated by the following formula : 



DRxDDooDD-hDR. 



A group of subjects who are capable under the above-mentioned 

 conditions of producing neuropathic offspring, who marry freely 

 into the general population, selecting mates more or less at ran- 

 dom, will show, by the relative frequency with which they pro- 

 duce neuropathic offspring, how common in the general popula- 

 tion are persons ivho carry the neuropathic taint. 



Among the subjects who figure in our charts and statistics 

 there are 466 who are theoretically classed as simplex, represented 

 by the symbol DR, namely, all the normal subjects who have 

 resulted from matings of the second and third types, two-thirds 

 of the normal subjects who have resulted from matings of the 

 fourth type, and one-half of those who have resulted from 

 matings of the fifth type. From this number must be deducted 

 179 who have not married or have married but have had no chil- 

 dren. From the remainder must be deducted further 66 subjects 

 who are among the direct ascendants of our patients, all of whom 

 have, of course, had neuropathic offspring, and who should ob- 

 viously not figure in such statistics. Of the remaining 221 sub- 

 jects, all of whom, if mated with neuropathic or simplex subjects, 

 were capable of producing neuropathic offspring, 70 actually had 

 such offspring and 151 had normal offspring. 



In other words, our data seem to show that no less than 51. d 

 per cent of the general population carry the neuropathic taint! 



It is interesting to note here that the districts in which our in- 

 vestigations have been carried out are, according to the statistics 



