Physical Growth From Birth to Two Years Ii. Head Circumference.

A few years ago the writer began a series of studies intended to aggregate and systematize the available research materials on selected items of physical growth during infancy. The first of these studies dealt with stature, and was published as a monograph (20). The second treats head circumference, and has been prepared in the form of two papers. The present paper the first of the two on head circumference presents a colligation of North American research to date for groups of infants. Its companion paper, to be published later, will bring together the studies made in North America on the growth of individuals. Readers should recognize that this division is merely a convenient device for reducing the problem to articles of journal length. In its scope, then, the present paper is restricted anthropometrically to girth of the head (occipito-frontal circumference), chronologically to the first two postnatal years, geographically to North America, secularly to the period from 1850 to 1945 (all of the presently accessible data having been collected between these dates), and analytically to the study of groups. These delimitations should be kept in mind; they constitute the frame of reference within which the contents of the paper are written and its conclusions claimed to hold.