EXPERIMENT STATION RECORD. 



Vol. XXXIII. Abstract Number. No. 3. 



RECENT WORK IN AGRICULTURAL SCIENCE 



AGHICULTTJRAL CHEMISTEY— AGROTECHNY. 



International catalogue of scientific literature. D — Chemistry {Internat. 

 Cat. Sci. Lit., 10 {1913), pp. F7/7+934; 11 {19U), pp. VIII +966). —The tenth 

 and eleventh annual issues of this catalogue (E. S. R., 27, p. 718), which contain 

 subject and author indexes for material received between October, 1910, and 

 October, 1911, and October, 1911, and October, 1912, respectively. 



Fibrin, A. W. Bosworth {New Yorlc State Sta. Tech. Bui. 41 {1915), pp. 

 8-6; Jour. Biol. Chem., 20 {1915), No 1, pp. 91-94).— While working with blood 

 certain observations seemed to indicate that fibrin might possess some chemical 

 properties quite similar to those of casein reported by L. L. Van Slyke and A. W. 

 Bosworth (B. S. R., 29, p. 9). 



It was found that " fibrin can combine with both bases and acids to form 

 definite compounds. Fibrin combines with four equivalents of base to form a 

 compound which is neutral to phenolphtbalein. Fibrin combines with bases to 

 form a series of three acid salts which contain one, two, and three equivalents 

 of base, resiiectively. All the combinations of fibrin with sodium, potassium, 

 and ammonium are soluble. The calcium fibrinates containing three and four 

 equivalents of calcium are soluble, the calcium fibrinates containing one and 

 two equivalents of calcium being insoluble. Fibrin combined with one equiva- 

 lent of acid is insoluble, and combined with more than one equivalent of acid 

 is soluble. Pui-e fibrin, unlike casein, is not strong enough as an acid to decom- 

 pose calcium carbonate. The molecular weight of fibrin is about G,666. Carbon 

 dioxid precipitates fibrin from a solution of calcium fibrinate, but not from a 

 solution of sodium, potassium, or ammonium fibrinate." 



The nature of the free amino groups in proteins, D. D. Van Slyke and F. J. 

 BiRCHARD {Jour. Biol. Chem., 16 {1914), iVo. 4, pp. 539-547).—" In all the native 

 proteins investigated the amount of free amino nitrogen is equal to one-half 

 the lysin nitrogen, no deviation exceeding the limit of experimental error of 

 the amino and lysin determinations being found in any case, with the possible 

 exception of gliadin, in which the difference is 0.7 per cent. The period required 

 for complete reaction of the proteins with nitrous acid (thirty minutes) is 

 longer than that required by the a-amino groups (three to four minutes), but 

 corresponds to that found for lysin, with a tt'-amino group free. The facts 

 support the following conclusions : 



"(1) One of the two amino groups of lysin, the w-group, exists free in the 

 protein molecule. (2) This group represents, within at most a fraction of a 



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