410 



EXPERIMENT STATION RECORD. 



[Vol. 43 



organic substances contained about 25 per cent of the total nitrogen of tlie 

 leaves. 



By applying similar methods to spinach leaves dried at lovv^ temperatures, 

 results were obtained so nearly identical with those obtained from the green 

 leaves as to indicate that the constituents of the cells were only slightly altered 

 by drying. 



" If, as seems probable, similar products can be made from other green 

 leaves it ought to be possible to feed tlie.se as the sole source of nitrogen and 

 thereby increase our knowledge of the nutritive value of a class of proteins 

 about which at present we know almost nothing. Possibly we shall also be 

 able to learn something of the nutritive value of the water-soluble constituents. 

 A new field for investigation appears to be thus opening which promises to be 

 fruitful." 



Some proteins froni the Georgia velvet bean, Stizolobium deeringianum, 

 C. O. Johns and H. C. Waterman (Jour. Biol. Chem., Jt2 (1920), No. 1, pp. 

 59-69). — An examination is reported of the proteins of the Georgia velvet bean 

 (8. deeringianum), a sport of the Florida velvet bean, a study of the proteins 

 of which has been previously noted (E. S. R., 39, p. 202). 



The Georgia variety was found to contain about 23.6 per cent of protein. A 

 yield of about 15 per cent of protein was obtained from the finely-ground seed 

 by a 3 per cent solution of sodium chlorid, aud by coagulation from the slightly 

 acidified extract at the boiling temperature a yield of 13 per cent of mixed 

 proteins was obtained. From the sodium chlorid extracts three tM)es of pro- 

 teins were separated: o-globulin precipitated by 0.4 saturation with ammonium 

 sulphate, coagulable at 70 to 78° C, and containing 0.9 per cent of sulphur; 

 ;5'-globulin precipitated from the extract by 0.6 to 0.7 saturation with am- 

 monium sulphate, coagulable at 90 to 100°, and containing 0.45 per cent of 

 sulphur ; and an albumin obtained by coagulation from aqueous extracts previ- 

 ously freed from globulin by prolonged dialysis, coagulable at 54 to 62°, and 

 containing 1 per cent of sulphur. The o-globuliu and the albumin gave strong 

 tests for tryptophan with Hopkins and Cole's reagent, while the jS-globulin r^l 

 gave no trace of this reaction. Attention is called to the fact that this is the 

 first vegetable globulin which has been found to contain no tryptophan. 



The percentages of the basic amino acids in the three proteins, as determined 

 by the Van Slyke method, are given in the following table : 



I 



Percentage of the basic amino acids in the proteins from the Georgia velvet tean. I '• 



The simple carbohydr/ites and the glucosids, E. F. Armstrong (London: 

 Longmans, Green d- Co., 19J9, 3. ed.. pp. IX-\-239). — In the preface of the third 

 edition of this monograph on carbohydrates and glucosids (E. S. R., 28, p. 710) 

 acknowledgment is made of the contributions of C. S. Hudson and associates, 

 of the Bureau of Chemistryj U. S. Department of Agriculture, as follows: 



" The relationship of optical rotatory power to structure in the case of the 

 carbohydrates has long been a source of speculation, but because of the ia- 



