710 EXPERIMENT STATION RECORD. [Vol.38 



" The inactivation of esterase and lipase preparations by acids, bases, neutral 

 salts, alcohols, acetone, esters, and heat led to the hypothesis that the active 

 enzym grouping in these substances possessed the enol-lactim structure, 

 — C(OH)=N — , which became inactive by tautomerization to the keto-lactam 

 structure, — CO — NH — . This hypothesis vpas tested by studying the actions of 

 such groupings in dipeptids and an imido ester." 



It was shown that '.' in the presence of simple peptids, esters are hydrolyzed 

 under conditions which favor the production in the former of the enol-lactim 

 grouping, that ethyl imidobenzoate, having the enol-lactim structure, possesses 

 marked ester-hydrolyzing action as well as certain properties strikingly analo- 

 gous to those of the naturally occurring lipolytic enzyms, and finally that, under 

 conditions under which the occurrence or formation of the enol-lactim structure 

 might be expected (action of alkali), ester-hydrolyzing substances are produced 

 from proteins." 



The method of specific coagulation applied to the ferments of the pan- 

 creatic juice, E. S. London and E. P. Pakhotina {Compt. Rend. Soc. Biol. 

 [Paris-l, SO (1911), No. 15, -pp. 75S, 759; abs. in Chem. Abs., 12 {1918), No. 1, 

 p. -^7).— By fractionating a mixture of the ferments of pancreatic juice by suc- 

 cessive treatments with ammonium sulphate ions according to the principle out- 

 lined on page 786, the authors were able to obtain a successive precipitation of the 

 different ferments. The aipylolytic ferment was precipitated first at a concen- 

 tration of ammonium sulphate of 20 gm. per 100, the proteolytic next at 30 gm. 

 per 100, and the lipolytic last at almost 50 gm. per 100. ' 



Improvements in bacteriological media. — I, A new and efficient substitute 

 for " nutrose," R. L. M. Wallis {Indian Jour. Med. Research, 4 {1917), No. 4, 

 pp. 786-796; Agr. Jour. India, 12 {1917), No. k, pp. 621-632; abs. in Chem. Abs., 

 12 {1918), No. 5, p. Ji93).— The new substitute for " nuti'ose " is composed of 94 

 parts peanut flour, 5 parts casein, and 1 part sodium carbonate. The product 

 consists of a very finely divided white powder with a sweet taste and a neutral 

 reaction. Its solution in hot water gives a faint opalescence due to the fat 

 still remaining in the peanut flour. Used in the Conradi-Drigalski culture 

 medium, it gives a transparent medium on which organisms of the typhoid-coli 

 group grow very rapidly. The property of stimulating the growth of organisms 

 is apparently due to the presence of a " vitamin " associated with the globulin 

 of the peanut flour. 



The author states that combined with egg white and a little salt the new 

 nutrose makes an excellent diabetic bread of high protein and low carbohydrate 

 content. 



A method for the preparation of uniform collodion membranes for dialysis, 

 C. J. Farmeb {Jour. Biol. Chem., 82 {1917), No. 3. pp. U7-453, fig. i).— An ap- 

 paratus is described by means of which uniform collodion dialyzing membranes 

 may be made. The permeability and time of dialysis may be established by 

 standardization with phosphate mixtures and may be changed by varying the 

 period of drying. 



Oxidation of ammonia to oxids of nitrogen, W. G. Adam {Chem. Trade 

 Jour., 62 {1918), No. 1606, pp. 181, 182. fig. 1). — A commercial converter is de- 

 scribed capable of producing one ton of nitric acid every 24 hours from synthetic 

 ammonia. The converter consists essentially of an aluminum box containing a 

 window for observation and having four close layers of platinum gauze held by 

 asbestos rings between aluminum flanges. The lighting up of the catalyst is 

 obtained by means of an electrically heated platinum spiral inserted in the mix- 

 ture of ammonia and air in close contact with the catalyst, a mixture richer in 

 ammonia being passed for a few seconds until the catalyst is sufficiently hot to 



