412 EXPERIMENT STATION RECORD. [Vol.36 



The reaction between amino acids and carbohydrates as a probable cause 

 of humin formation, M. L. Roxas (Jour. Biol. Chem., 27 (1916), No. 1, pp. 

 71-93). — From a study of the effects of various amino acids and carbohydrates 

 as a factor in humin formation during the hydrolysis of proteins, the author 

 found that alanin, leucin, phenylalanin, and glutaminic acid are not important 

 factors in humin formation. Prolin may, however, be involved in the humin 

 formation under certain conditions. In digestion with 20 per cent hydro- 

 chloric acid plus sugar the proportion of nitrogen disappearing and responsible 

 for humin formation was for tyrosin, 15 per cent ; cystin, 3.1 ; arginin, 2.33 ; 

 lysin, 2.62; histidin, 1.84; and tryptophan, 71 per cent. Xylose and fructose 

 were generally more reactive than glucose. 



Arginin, histidin, and lysin reacted with sugars more readily in weak acid 

 or aqueous than in strong acid solutions. Arginin, histidin, and tryptophan 

 reacted with a loss of their amino nitrogen, but tyrosin and cystin reacted 

 without any such loss. It appears thus that it is not the amino group of either 

 tyrosin or cystin that reacts with the carbohydrate to form melanin, but 

 probably the Oil group in the former and the sulphur linking in the latter. 



A possible mode of reaction between the amino acids and the carbohydrates 

 or some degradation product is suggested. 



Experimental results are submitted in detailed tabular form. 



Tyrosinase and deaminization, K. Schweizeb (Tyrosinase et D^samination. 

 Thesis, Univ. Geneva, Inst. Bot., No. 573 (1916), pp. 117).— The study reported 

 is considered under the following topics : History, distribution, preparation, 

 properties, action, constitution, and synthesis of tyrosinase; general considera- 

 tions of deaminization ; deaminization by tyrosinase ; deaminization by 

 tyrosinase in the presence of phenol ; deaminization by tyrosinase in the pres- 

 ence of chlorophyll ; and deaminization under anaerobic conditions. 



It is concluded that deaminization is not necessarily produced by hydrolytic 

 enzyms, but very readily by oxidases, tyrosinase in particular. The existence 

 of hydrolytic deaminases is rendered highly problematical. The cleavage prod- 

 ucts of deaminizations by tyrosinase are ammonia, carbon dioxid, and a 

 fatty acid with one less carbon atom than the original substrate. In the animal 

 organism tyrosinase is active in the formation of urea by the degradation of 

 polypeptids and amino acids, not through simple hydrolysis but by oxidation. 



A complete list of references to the literature cited is included. 



The chymase of Solanum elasagnifolium. — A preliminary note, A. Bodan- 

 SKY (Jour. Biol. Chem., 27 (1916), No. 1, pp. 103-105).— The author has found a 

 chymase in /S. ekragnifoliuia (white horse nettle) the properties of which agreed 

 in general with those of other vegetable chymases. It coagulates boiled natural 

 milk without the addition of calcium chlorid, is more resistant to heat than 

 rennin, and obeys the enzym laws in general. 



The possible adoption of the enzym preparation by cheese makers as a sub- 

 stitute for remiet extract is indicated and will be further studied. 



The preparation and properties of lead-chlor arsenate, artificial mimetite, 

 C. C. McDonnell and C. M. Smith (Amer. Jour. Set., 4. ser., 42 (J916), No. 2.'fS, 

 pp. 139-145, figs. 2). 



Methods for chemical and microscopical diagnosis, F. A. Steensma 

 (Methodcn der Chemische en Microscopische Diagnosiiek. Amsterdam: SchcJ- 

 tema & Holkema, 1915, 3. ed., rev. and enl., pp. 157). — This volume outlines 

 methods for the examination of urine, urine sediment, blood, gastric contents, 

 feces, sputum, pus, exudates and transudates, cerebrospinal fluid, semen, milk, 

 specimens of hair and epithelial tissue, and concretions, and includes notes 

 on the medico-legal examination of such material. Only those methods which 



