The polymorphonuclear leukocytes of the new-born infant show a preponderance of the single and double lobed nucleated forms. Under normal conditions there is a rapid tendency for the multilobed forms to appear, and the polymorphonuclear cells to assume adult form.1 This characteristic change may be influenced toward a shifting back to the young single-lobed nucleated cells by the utraviolet light.2 It was, therefore, considered desirable to study the action of the irradiated produce, "viosterol," on the blood of the new-born infant.
METHOD
This study is based on a series of forty new-born infants observed during a period of six months. The differential counts were made within six hours after birth and at intervals of twenty-four hours thereafter. The determinations were made at the same time every day. The slides were stained with carbol-pyronin,3 the films being dried in air and the stain applied for fifteen minutes. No preliminary