310 EXPERIMENT STATION RECORD. [Vol.38 



The solubility of silica, V. Lenher and H. B. Merrill {Jour. Amer. Chem. 

 Soc, 39 (1917), No. 12, pp. 2630-2638, figs. 2).— Data on the solubility of silica in 

 water and in hydrochloric and sulphuric acids are reported in tabular and 

 graphical form. 



The solubility was found to be definite and to depend on the temperature and 

 concentration. With gelatinous silica, equilibrum was reached in a few hours 

 or, at most, in a few days. Equilibrium could not be obtained with ignited 

 silica in days or weeks. The solubility of the gelatinous silica was found to be 

 the same regardless of the method of preparing tlie gel. The true solubility of 

 ignited silica is deemed to be the same as that of gelatinous silica, but satura- 

 tion is not reached in any short period of time. The apparent .solubility is 

 somewhat less than that of gelatinous silica. 



Study of the preparation of ammonium nitrate by double decomposition 

 between sodium nitrate and ammonium chlorid, E. Rengade (Rev. G&n. Sci., 

 28 (1911), No. 17-18, pp. 489-503, figs. 4).— The author has studied the reaction 



NaNOs+NHiOl^riNHiNOa+NaCl 

 and has determined the optimum conditions for obtaining the largest yield of 

 ammonium nitrate. The data are submitted in tabular and graphical form and 

 discussed. 



The nitrogen distribution in protalbinic and lysalbinic acids, Cornelia 

 Kennedy and R. A. Gortner (Jour. Amer. Chem. Soc., 39 (1911), No. 12, pp. 

 2134-2136). — The authors, at the Minnesota Experiment Station, prepared pro- 

 talbinic and lysalbinic acids by the action of alkali on egg albumin, and deter- 

 mined the nitrogen distribution in these substances, as well as in the original 

 egg albumin, by Van Slyke's method (E. S. R., 26, p. 22). 



No marked differences were observed in the nitrogen distribution of these sub- 

 stances and the egg albumin. Both the acids showed a somewhat greater ap- 

 parent lysin content than the original egg albumin. This is considered due to 

 the presence of ornithin, derived from arginin by the action of the alkali. 



It is noted that the results presented " furnish no evidence as to whether 

 or not the protalbinic and lysalbinic acids are true chemical compounds or as to 

 whether or not their chemical structure is more simple than is that of egg albu- 

 min. It is extremely improbable, however, that either preparation has as low 

 a molecular weight as 800. " 



The effect of prolonged acid hydrolysis upon the nitrogen distribution of 

 fibrin, with especial reference to the ammonia fraction, R. A. Gortner and 

 G. E. Holm (Jour. Amer. CJiem. Soc., 39 (1911), No. 12, pp. 2136-2145, fig. 1).— 

 The authors, at the Minnesota Experiment Station, hydrolyzed fibrin with 20 

 per cent hydrochloric acid for various periods of time, ranging from one hour 

 to six weeks, and analyzed the resulting hydrolysates. 



From the data obtained, it is concluded that the figures for ammonia nitrogen 

 in an acid hydrolysate are not necessarily a true measure of the amid nitrogen 

 in the protein molecule, but that they also include some ammonia derived from 

 the deamination of certain of the amino acids, the extent of the deamination 

 depending upon the length of hydrolysis. Monoamino acids are considered to 

 be much more easily deuminized than the histone bases. Cystin is not the only 

 amino acid which undergoes deamination when boiled with hydrochloric acid. 



" The figures for arginin, histidin, and lysin in a Van Slyke analysis are not 

 appreciably altered by a hydrolysis extending over six weeks, pi'oviding that all 

 tryptophan has been so altered that it does not precipitate on the addition of 

 phosphotungstic acid. If it does precipitate it will be calculated as histidin. " 



Increases in the insoluble humin nitrogen, due to prolonged hydrolysis, are 

 regarded as due to carbonization. It is noted, however, that there is no means 

 of proving or disproving this hypothesis at present. 



