I9I2.] 



ANALYZED BY THE MENDELIAN METHOD. 



189 



are of the type simplex X simplex, and the findings would seem to 

 indicate that all the matings are of this type. 



Duplex X Duplex. 



Under this type of mating we have grouped all those fraternities 

 in which both parents are recorded as normal. 



In the study of seventy-six fraternities there were 441 concep- 

 tions; 62 are too young for classification or entirely unknown, 103 



'Q^O 



D-r-O 





(yfoi^/p 





111 I 1 



IE SI In] o (S 



^O m^^ 



Fig. 10. This chart shows the mating of two normals. They each have 



defective relatives. Of the seven children the fourth is an epileptic and the 



others seem to be normal. E, epileptic; F, feeble-minded; A, alcoholic; A'^, 

 normal. Case 2,983. 



died before the age of 14 years. Of the 276 others, 172 are normal, 

 75, or 22 per cent., are epileptic and 3, or i per cent., feeble-minded, 

 w^ith I insane and 25 tainted, that is, 197 ( 172 -|- 25), or 71 per cent., 

 are duplex or simplex in character. (Fig. 10.) 



The results show that these normal parents are not duplex, but 

 simplex, and a study of their ancestors justifies this conclusion, for 

 in at least 45 of the matings, one or both of the parents descended 

 from tainted ancestors. 



PROC. AMER. PHU., SOC. , LI. 205 J, PRINTED JULY 23, I9I2. 



