804 EXPERIMENT STATION RECORD. 



Dilatometric investigation in regard to the precipitation of proteins, G. 

 Galeotti (Hoi)pe-Seyler's Ztschr. Phynol. Chem., IS {1912), No. 6, pp. 42I-W, 

 flg^ i). — No variation in volume takes place during the coagulation of proteins 

 by either euzyms or heat. During the precipitation of egg albumin with the 

 so-called precipitating reagents an increase in volume takes place, which is 

 dependent uix)n and differs with the precipitating reagent employed. It is 

 greatest with ammonium sulphate, less with the salts of beavy metals, and 

 least with potassium ferrocyanid, phosphotuugstic acid, and tannic acid. 



The progressive hydrolysis of fats, A. GRiJN and O. Cohelli (Ztschr. 

 Angetc. Chan., 25 {1912), No. I4, pp. 665-670; ahs. in Jour. Soc. Chem. Indiift., 

 31 {1912), No. 9, p. H2). — When pure tripalmitin was treated for several hourt^ 

 with sulphuric acid of 66° B. at 70° C. in the proportion of 10 molecules of 

 acid to 1 of glycerid, a fatty acidity equal to 56.5 per cent was obtained. This 

 shows that a diglycerid is produced from a triglycerid without the production 

 of mono-glycerid. Similar results were obtained when tristearin was treated 

 in the same way. Attempts to isolate intermediary products failed. 



The hydrolysis and constitution of lecithin, F. Malengkeau and G. Prigent 

 {Hoppe-Heylcrs Ztschr. Physiol. Chem., 77 {1912), No. 2, pp. 107-120) .—The 

 authors found that it w^as possible with the aid of heat to hydrolize lecithin 

 completely with either a decinormal sulphuric acid solution or a decinormal 

 hydrochloric acid solution. The process takes about 5 or 6 hours, but has the 

 advantage of not leaving an excess of acid present at the end- of the process. 

 Cholin does not influence the reaction. 



Note on hydrolysis of vegetable oils by emulsion of Bicinus communis, 

 D. SoMMERViLi.E {Bio-Chcm. Jour.. 6 {1912), No. 2, pp. 253, 25',).— ^o difference 

 was noted in the amount of hydrolysis with castor oil or cotton-seed oil when 

 treated with an emulsion of the castor bean, therefore it is concluded that the 

 enzym of the castor bean does not act si)ecifically toward its own oil. The 

 author was not able to note any acceleration of hydrolysis by acetic acid and 

 manganese sulphate. The lipase of the castor bean was not refractory to heat 

 when protected by oil. Heating the emulsion to 60° C. destroyed the enzym. 

 The bean from which the emulsion was obtained was stable when heated at 

 100° for 24 hours. 



" Cotton oil and castor oil, when carefully neuti-ftlized and freed from pro- 

 teins fail to undergo hydrolysis. If to this oil an enzyniic emulsion, in which 

 hydrolysis of fat has not yet commenced, be added, nothing results. If hydrol- 

 ysis is established in the emulsion, the hydrolysis proceeds in the added oil, 

 irrespective of whether this oil be neutral or contain within wide limits (25 

 per cent) free fatty acids." 



The hydrolysis of saccharose by various acids in the presence of invertase, 

 C. Bertrand, M. and Mme. M. Rosenblatt (Bill. i^oc. Chim. France, .'/. ser., 11 

 (1912), No. !,, pp. 176-1S6; abs. in Jour. Soc. Chem. Indus., 31 (1912). No. 6. 

 p. 294; Ztschr. Angeiv. Chem., 25 (1912), No. 21, p. 1083).— It is concluded that 

 with invertase and perhaps with other soluble ferments we must assaume that 

 in the presence of specific colloidal substances the activity of the acid does 

 not depend entirely upon the hydrogen ion which results from the electrolytic 

 dissociation, but is also greatly dependent upon the nature of the radicles or 

 anions to which the hydrogen in the acid molecule is bound. 



An unrecognized source of error in the Kjeldahl-Gunning method for the 

 determination of nitrogen, P. A. W. Self (Pharm. Jour. [London], ',. ser., 

 34 (1912), No. 2527, pp. i^,S,J, 38J).— The author sought to ascertain the cause 

 for the low results which were often obtained with the Kjeldahl-Gunning method 

 when comparatively large amounts of material were employed. The results of 



