16% nitrogen from the value of 9.6% found on a Kjeldahl determination on the hydrolyzate. These final values are given in Table I1 with those determined in the same manner by adding valine rather than leucine. Table I1 includes the values reported by Greenberg (6) for the composition of gelatin; they are in good agreement with the duplicates reported here. Gas phase chromatography of the 1vacetylated butyl esters of amino acids can be used for the quantitative determination of these six amino acids. Horn far the method can be extended to include additional ones remains to be seen. A number of peaks were obtained beyond proline for the gelatin hydrolyzate and work is continuing to identify these and to see if quantitative data can be obtained. It is likely that there will be difficulty M-ith acids such as cystine, tyrosine, arginine, histidine, and lysine. LITERATURE CITED
(1) Baver. E.. Reuther. I
