Abstract
The average growth changes of the stature and body weight of JapaneseAmerican hybrids who live inwelfare homes for children in Japan were analysed. The complete longitudinal data of 36 boys and 21 girls were used.
1) It did not affect the growth of the stature and body weight of the hybrids whether their fathers were whites or negroes.
2) As compared with their parental groups, the hybrids were as tall as the Japanese at the age of 6 years, but they were placed in an intermediate position between the whites and Iapanese at the age 15 years. The body weight of the hybrids Wa s very close to that of the Japanese at the age of 6 years, but tended to apProach that of the whites by the age of 15 years. These findings suggest that the growth in the prepuberal period depends upon environmental conditions, and that hereditary influences appear first at adolescence.
3) The peak velocity in the adolescent growth was reached almost at the identical age period in the hybrids, whites, and Japanese, but the annual gain at peak was considerably greater in the hybrids than in the others. Whether this high degree of acceleration at adolescence would be essential to the hybrids was discussed.
