Preliminary to beginning some studies on the amino-acid metabolism of infants and children, it was deemed advisable to obtain figures that would establish with reasonable accuracy the normal fasting amino-acid content of the blood. Owing to the comparatively short period of time that has elapsed since the development and introduction of the Folin method1 of amino-acid determination, the literature, to date, contains no such observations for use as normal standards.
In the accompanying tables are submitted the results of studies made by the Folin method in fifty cases selected to range from infancy to puberty.
To carry on these observations, it was necessary to choose subjects already in the hospital. While these, of course, are hospital cases they are hospital normals so far as their selection can be controlled. Only patients whose convalescence was definitely established, in whom no kidney impairment existed and whose temperatures were normal were observed.