202 EXPERIMENT STATION RECOED. IVol. 43 



A new method for preparing esters of amino acids. — Composition of 

 caseinogen, F. W. Foreman {Biochem. Jour., 13 {1919), No. 4, pp. 318-397). — 

 The method of preparing estei-s of amino acids by the hydrolysis of their dry 

 lead salts with dry hydrochloric acid gas (E. S. R., 27, p. 501) has been appUed 

 to the products of the hydrolysis of casein by sulphuric acid and by hydrochloric 

 *icid, the former to determine the distribution of the nitrogen in the various 

 fractions and to test the completeness of the esterificatiou, and the latter to de- 

 termine the effect of the process upon the yield of the nonamino acids and to 

 throw some light upon the nature of the unidentified substances making up the 

 deficit in protein analysis. 



The hydrolysis with sulphuric acid showed that no less than 7 per cent of 

 the nitrogen was lost in the barium sulphate precipitate formed when the acid 

 was removed. The crude ty rosin contained 1.98 per cent of the total nitrogen, 

 and the aqueous solution of amino acids from which the lead salts were pi^- 

 pared for esterification 88.38 per cent of the nitrogen. On precipitating the 

 lead fe'alts from the aqueous solution of amino acids 77.08 per cent of the total 

 nitrogen was recovered in the dry lead salts, and in the filtrate containing the 

 ester hydrochlorid after removing the lead chlorid the recovery was 75.02 per 

 cent. 



The percentage of nonamino acids recovered after the hydrolysis of caseinogen 

 with hydrochloric acid and subsequent treatment according to the author's 

 methods was as follows : Glycin 0.45, alauin 1.85, valin 7.93, leucin 9.7, prolin 

 7.63, and phenylalanin 3.88 per cent. The unesterified residue consisted largely 

 of a sirupy niaterial which was afterwards separated directly from the hydro 

 lytic products, together with glutaminic and aspartic acids in the form of 

 alcohol-insoluble salts*. The yield by this modification was glutaminic acid 

 21.77, aspartic acid 1.77, and sirups 14.34 per cent. By adding to these figures 

 of nonamino acids 3.41 per cent of luiknown substances probably of peptid 

 nature, 7. 02 per cent of lysin, as reported by Van Slyke (E. S. 11., 33, p. 408), 

 and as figures for the other amino acids, ammonia, sulphur, and phosphorus 

 the results selected by Osborne and Guest as most reliable (E. S. R., 25, p. 504), 

 a total of 97.36 per cent was obtained. It is pointed out that as some of the 

 products include the water of hydrolysis the total should be greater than 100 

 per cent. 



The iron content of oils, fats, waxes, resins, gum resins, and gums; to- 

 gether with some determinations of silica and aluminum, M. Gonnekm.vnn 

 (Biochem. Ztschr., 95 {1919), No. 5-6, pp. 286-295). — Determinations of the iron 

 content of animal and vegetable fats and various waxes, resins, and gums are 

 reported. Iron was found in amounts varying from a trace to as much as 29.7 

 per cent of the ash in all the substances examined, with the exception of the 

 lipoids of horses' brains and Senegal gum. 



A table is also given of determinations of silicic acid and aluminum in vari- 

 ous plant and animal substances. 



On the synthesis of sugars from formaldehyde, carbon dioxid, and 

 water, A. J. Ewart {Proc. Roy. Soc. Victoria, n. ser., 31 {1919), No. 2, pp. 

 S7S-5S7, pi 1). — In continuation of work previously noted (E. S. R., 42, p. 527), 

 the author reports investigations on the polymerization of formaldehyde to 

 sugar by alkalis and alkaline carbonates. 



" The main conditions for a high proportion of sugar are appropi'iate dilu- 

 tion and a temperature of 100° C. to 110° C, The by-products are formates 

 and methyl alcohol mainly. At low temperatures little or no sugar is pro- 

 duced. The most rapid reaction is produced by sodium hydrate. In the pres- 

 ence of a neutral calcium salt tlie amount of sugar condensation is gi-eatly in- 



