176 



SCIENCE 



[N. S. Vol. LIV. No. 1391 



a product was isolated from the urine which has 

 been identified as the phenyluramino derivative of 

 cysteine. 

 Avian versus mammalian dietary requirements: 



W. D. BiCHARDSON. 



The influence of fasting and of vitamins B 

 deprivation on the non-protein nitrogen of rat's 

 Hood: H. A. Mattill. The non-protein nitrogen 

 of the blood of fasting rats is 30-40 per cent, 

 higher than that of normal animals, the most 

 marked increase being in urea. Creatinine and 

 creatine are very slightly increased as are total 

 solids. The blood of rats deprived of vitamine B 

 shows practically no variation from the normal 

 except that creatinine is at the fasting level and 

 creatine is slightly higher than the fasting fig- 

 ure. In the present state of uncertainty with ref- 

 erence to the determination of blood creatine and 

 creatinine these variations are of little significance 

 but at least the total solids, the non-protein nitro- 

 gen and the urea fraction in the blood of rats on 

 a diet deprived of vitamine B are normal and not 

 increased as in the blood of fasting rats. The 

 desirability of obtaining information on the 

 gaseous metabolism as well as on creatine metab- 

 olism in animals deprived of vitamine B is sug- 

 gested. 



The effect of temperature and the concentration 

 of hydrogen ions upon the rate of destruction of 

 the antiscorbutic vitamin: H. C. Sherman, V. 

 K. LaMer and H. L. Campbell. The time curve 

 of the destruction in filtered canned tomato juice 

 follows neither the unimolecular nor the square 

 root law of Schiltz when the heat treatment is 

 conducted at 60°, 80°, 100° C. for 1 to 4 hours. 

 Empirically the destruction in these cases was 

 found to be a function of the fourth root of the 

 time. The temperature coef&cient of the de- 

 struction of the vitamin was low: Q^ (60°-80°) 

 = 1.23; 0,0 (80°-100°)=1.12. The low tem- 

 perature coefiicient and the colloidal nature of the 

 material indicate that in tomato juice, at least, 

 the reaction is of the heterogeneous type with dif- 

 fusion playing an important rOle. Oxidation by 

 oxygen can not be an important factor in these 

 experiments. The velocity of the reaction at 1 

 hour at 100° C. progressively increases with de- 

 creased (H*). The omission of reacidification 

 following such treatment produces an even greater 

 destruction due no doubt to the continued action 

 of the greater (OH") even at low temperature. 



The quantitative measurement of the antiscor- 

 butic vitamin: H. C. Sherman, V. K. LaMer and 



H. L. Campbell. Guinea pigs are fed a basal 

 diet consisting of oats 59 per cent.; skim milk 

 powder heated 2 hours at 110° C, 30 per cent.; 

 butter fat, 10 per cent. ; NaCl, 1 per cent. In ad- 

 dition to the determination of the miuimum pro- 

 tective dose of antiscorbutic the degrees of scurvy 

 produced, as measured by the autopsy findings, 

 retardation in growth, and symptoms in life, are 

 determined for a series of animals receiving gradu- 

 ated sub-protective doses of antiscorbutic food. 

 When the dosage is calculated per unit of body 

 weight it is possible to distinguish the degrees of 

 scurvy produced for addenda of antiscorbutics 

 differing by 15 per cent, or less. The per cent, de- 

 struction due to a deleterious process is obtained 

 by comparison of the degree of scurvy produced 

 in a series of standard animals fed a similarly 

 graduated series of doses of the treated product. 

 The probable error of the mean in a series of 5 

 or more animals is less than 4 per cent. 



The action of nitrous acid o»i casein: Max S. 

 Dunn and H. B. Lewis. Deaminized casein has 

 been prepared by the action of nitrous acid on 

 casein. Analysis by the Van Slyke method for 

 free amino nitrogen showed the absence of free 

 amino nitrogen. Casein and deaminized casein 

 were hydrolyzed and analyzed by Van Slyke 's 

 procedure for the determination of characteristic 

 groups. In harmony with the current theories as 

 to the nature of the free amino groups of the 

 protein molecule, lysine was found to be absent 

 in deaminized casein. No other notable differ- 

 ences were detected between casein and deaminized 

 casein. Tyrosine was determined by the Folin- 

 Denis colorimetric method. Deaminized casein 

 was found to contain a lower percentage of tyro- 

 sine than casein. 



Lipase studies. The hydrolysis of the esters of 

 some dica/rboxylic acids iy the lipase of the liver: 

 A. A. Christman and H. B. Lewis. On the basis 

 of the acidity developed when the lipase of hog 

 liver was allowed to act on the diethyl esters of 

 succinic and malonic acids, it is considered that 

 the reaction proceeded to an equilibrum which 

 corresponded to the removal of one ethyl group 

 from the diethyl esters. A substance was ob- 

 tained from the products of the reaction between 

 diethyl malonate and lipase which gave on analysis 

 figures which were in good agreement with those re- 

 quired for monoethyl malonate. Lipase of hog 

 liver was not able to hydrolyze monoethyl malonate 

 or potassium ethyl malonate. 



