1917] AGRICULTURAL CHEMISTRY — AGROTECHNY. 109 



of Gortner and Blish, previously noted (E. S. R., 35, p. 311), the author at the 

 Minnesota Experiment Station lias found that the amount of ammonia nitrogen 

 in a protein hydrolyzate is not significantly altered when hydrolysis is carried 

 out in the presence of a quantity of carbohydrate equal to three times the 

 weight of the protein material. 



If the weight of carbohydrate material present greatly exceeds the amount 

 of protein an accurate nitrogen distribution by Van Slyke's method can not be 

 obtained. The amount of humin nitrogen is greatly increased by the presence 

 of carbohydrate, probably because of both chemical and physical causes. 

 Tryptophan can not be accurately estimated by hydrolyzing proteins in the 

 presence of carbohydrates. When fibrin is hydrolyzed in the presence of fur- 

 fural the humin nitrogen is greatly increased. This increase is deemed due not 

 only to a chemical reaction in which certain amino acids combined with furfural, 

 but also to adsorption or occlusion of other araiuo-acid nitrogen by the humin. 

 When furfural is boiled with strong hydrochloric acid appi'oximately 75 per 

 cent by weight is converted into a black insoluble mass. It is suggested that 

 perhaps the humin, " formed from carbohydrates by boiling with hydrochloric 

 acid, is actually formed from furfural, which is in turn formed from the 

 corbohydrate." 



When fibrin is hydrolyzed in the presence of benzaldehyde the humin nitro- 

 gen rises rapidly to a maximum of approximately double the amount produced 

 in an ordinary hydrolysis. " The reaction here appears to be wholly chemical. 

 The ammonia nitrogen is not significantly altered, although there is evidence 

 that some deamination takes place." When fibrin is hydrolyzed in the presence 

 of formaldehyde an Initial gain of humin when small amounts of formaldehyde 

 are used is observed, but a large loss when greater quantities of the aldehyde 

 are present. 



" Both tryptophan and tyrosin yield a very considerable proportion of * acid- 

 insoluble ' humin nitrogen when boiled with hydrochloric acid in the presence 

 of benzaldehyde. AVhen tryptophan is boiled with formaldehyde, in the presence 

 of hydrochloric acid, a very considerable part of the nitrogen Is retained in the 

 acid-insoluble humin. This is in decided contrast to the behavior of tryosin, 

 where no acid-insoluble humiu is formed, but where a greater or less percentage 

 of the nitrogen is retained in the ' acid-soluble ' humin, the amount retained 

 depending upon the quantity of formaldehyde present. Some deamination 

 occurs in both amino acids, when heated with either aldehyde, in the presence 

 of hydrochloric acid." 



It is indicated that " when nitrogenous compounds other than proteins are 

 present in a hydrolyzate no reliance can be placed upon the figures obtained in 

 any of the fractions, as representing actual amino acids. Such data should 

 not be compared with those ol)tained by the analysis of pure proteins." 



Formation of hematoporphyrin in ox muscle during autolysis, R. Hoag- 

 LAND iU. 8. Dept. Agr., Jour. Agr. Research, 7 (1916), No. 1, pp. //MJ).— Ex- 

 perimental data obtained in the course of a study of autolysis in ox muscles 

 demonstrate that the striated muscular tissue of the ox contains enzyms which, 

 under anaerobic conditions, readily reduce oxyhemoglobin to hematoporphyrin. 

 The probability that hematoporphyrin may be a regular intermediate product 

 in the transformation of hemoglobin into bile pigments is indicated. 



The autolyses studied covered periods ranging from 7 to 220 days. 



Biochemical reaction of rancid fats, J. Vintilescu and A. Popescu (Bui. 

 Chim. [Bucharesfi, 17 {1915), pp. 145-150; abs. in Chem. Zenthl., 1916, I, No. 

 5, p. 235). — Fats which have become rancid and have been exposed to the air 

 absorb oxygen, which can be liberated through peroxidase. The oxygen ab- 



