analyzed the essential oil of Japanese peppermint (Mentha arvensis var. piperescens) obtained from two strains of that plant grown in Florida during four successive years. The menthol content of the oil was somewhat low, the average values on the two strains being 67 per cent. and 71 per cent., respectively. The menthol content was fairly uniform from year to year. The per cent. of the total menthol present as esters was relatively low. However, the plants, apparently, do not adapt themselves well to the hot climate of Florida.
J. S. H.
Methionine Content of Proteins.--Methionine is alpha amino gamma methylthiol normal butyric acid. It was discovered in tbe proteins in 1921, and is one of the comparatively few sulphurcontaining segments of the protein molecule. HARRY D. BAERN-STEIN (Jo~tr. Biol. Chem., 1932, XCVII, 663-668) has determined the methionine content of 37 proteins; the lowest value obtained was 0.54 per cent. in the peanut protein arachin, the highest value 5.29 per cent. in albumin.
In a second paper, BAERNSTEIN (.Tour. Biol. Chem., I932, XCVII, 669-674) reports a study of the partition of the sulphur in 32 purified proteins, with special reference to methionine and the sulphydryl-disulphide (cysteine-cystine) sulphur. Expressed as per cent. of the total sulphur of the protein, the methionine sulphur ranged between 26.0 and 90.0 per cent., while the sulphydryldisulphide sulphur ranged between 17.7 and 84.3 per cent.
J. S. n.
Occurrence of Caffeine in Cereal
Beverages.--CHARLES H. LA