Recent studies have offered an abundance of evidence which indicates that night blindness is caused by vitamin A deficiency. Both adults and children have been used to investigate the relationship between vitamin A deficiency and night blindness.

Because of the paucity of evidence with regard to dark adaptation and the vitamin A status of pre-school children, this study is made. The purpose, therefore, is to add to the available data on this subject through an investigation of the bio-photometer as a means of detecting vitamin A deficiency in pre-school children.

The present study is part of a long time cooperative study of the Education and Home Economics Departments of North Texas State Teachers College begun in 1940. The purpose is to compare the dark adaptations of second and third grade children made in 1940 with those made in 1941, and to determine also the dark adaptation of a group of fifth and sixth grade children receiving vitamin A concentrate.