The Digital Formula in Japanese Fetus. II. Study on the Relative Length between the 1st toe and 2nd toe^*.

Abstract

The author has made the investigation of the relative length between the first and the second toe in 1308 cases of the Japanese fetuses, of which 700 are males and 608 are females, from the 4th month to the end of gestation.
In cases where the first is longer than the second toe, thefoot in question is of tibial type (T-type); in fibular type (F-type) the second toe is longer than the first toe, in the transitional type both toes are equally prominent (O-type).
1. Disregarding the gestation month, the order of frequencies of three types is F-> T-> O-type and ratio is 4: 2: 1. In this instance, there is no difference in sexes, and sides.
2. The frequency of the homo- type in the type combination of both sides is about 90% and the hetero-type is very low. Among the ho\mo-types, the F-F-type is (about 50%) first, the T-T-type is second, and the O-O-type is the third, (Table 5) but, among hetero-types, there are no clear difierencies in the frequency. And also, we can't find that there is the difference between both sexes.
3. When we investigate the freq u ency of each types in dividing materials into every 2 weeks of gestation, we find that the frequencies of the F-type and the O-type are inversely proportional to gestation month and the T-type increases in proportion to gestation month. The frequency-curves of the O- and the T-type are crossed at the first half of the 6th month and both curves of the F- and the T-type are crossed at the first half of the 9th month.
The order of frequency prior to th e 6th month is F-> O-> T-type; that of the period between the 6th and 9th month is F-> T-> 0-type; and that after the 9 th month is T->; F-> O-type.
4. It is interesting that there is racial difference among the white, the negro and the Japanese in the frequence of each types and change of the frequency with the progress of gestation month when we compare my data with that of A. H. Schultz.