798 MEMOIRS NATIONAL ACADEMY OF SCIENCES. [vol.xv, 



In the cases of 51 native-born whites, 22 negroes, and 11 foreign-born whites, psychoses 

 were diagnosed. In many of these instances, psychotic conditions were coupled with feeble- 

 mindedness. 



Three hundred and nine clinical examinations furnished the basis for mental-age reckonings. 

 The distributions for whites and negroes separately have been included in table 333. The 

 average mental ages are as follows: 



96 native-born Caucasians 7 years, 11^ months. 



159 Negroes 5 years, 6 months. 



45 foreign-born Caucasians 7 years. 



300 total group 6 years, 10 months. 



Ten native-born whites, 108 negroes, and 29 foreign-born whites never went to school. 

 Nine native-born whites, 8 negroes, and 1 foreign-born white attended school for less than one 

 year. Of the total group, 147 did not attend school and 18 spent less than one year in a class- 

 room. 



The average attendance time" of subjects having one or more years in school is as follows: 



77 native-born whites 6.00 years. 



43 negroes 3 -51 years. 



15 foreign-bora whites 5.20 years. 



135 total group 5.12 years. 



The coefficient of correlation between periods of school attendance and mental ages is 0.54. 



The second, first, third, and fourth grades show the greatest frequency numbers, having 

 31, 30, 23, and 23 cases, respectively. Of the whole group 53.3 per cent are illiterate. One 

 individual had completed high-school course and one was a college graduate. 



The coefficient of correlation between school grades and mental ages (140 cases) is 0.64. 



The rural type preponderates in the cases studied. Not only the 150 farmers but also a 

 great many of those listed as drivers, laborers, railroad section hands, woodsmen, etc., are of 

 country origin. Almost without exception, the foreign-born subjects were of the lower peasant 

 type, whde a very small proportion of the negroes could be termed urban dwellers. Approxi- 

 mately 32 of the native whites were city-born. 



The natural difficulties attendant upon attempts to obtain sex histories of subjects during a 

 single interview were complicated by language difficulties, low mentality, psychoses, and lack 

 of frankness on the part of many individuals. The data secured are therefore fragmentary. 

 Habitual masturbati;'i was acknowledged by 23 native-born whites, 5 negroes, and 1 foreign- 

 born white. Eleven whites claimed that they had never had sexual intercourse. One case of 

 infantile sex development, one of beastiality, and two of chronic enuresis were found. 



