Abstract
In earlier papers in this publication 1 , 2 we have suggested the following empirical formulá for the relation between body-length and age, and between body-length and body-weight:
In these formulá, T is the menstrual age in fetal or lunar months, L is the total or crown-heel length of the body in centimeters, W d is the weight of the dead body in grams, and W 1 is the body-weight in the living in grams.
To these may be added another expression for the relation between body-length and age, namely:
(4) T = 2.134 + 0.1L + 0.0011:L 2 .
The ages computed by this formula for 5 cm. stages of body-length from 5 to 50 cm. inclusive, show an average absolute deviation of 0.063 fetal months, or 1.77 days from the corresponding observed values of Mall 3 as determined by interpolation. The average percentage deviation is 1.28. While these deviations are somewhat larger than those of formula (1) above, the present expression is more useful, for it holds good from 2.5 fetal months to birth, whereas (1) holds good only above three fetal months.
A formula for the relation between age and body-weight may be obtained from (4) by substituting weight in terms of length as given in (2). This is:
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