"Calvin," Vahlen's Active Principles of Ergot. 121 



Analysis of the leucin fractions of casein and edestin gave the 

 following results, those obtained by Abderhalden being given for 

 comparison. The figures represent yield in grams from 100 grams 

 of protein. 



Casein. Edestin. 

 V-S. and L. Abderhalden. V-S. and L. Abderhalden. 



Leucin, 7-84) „ 



, , . f lo.S 8.1 20.9 



Isoleucin, i-5i ) 



Valin, 6.69 1.0 5.6 0.45 



Total " leucin fraction," 16.04 II. 5 13.7 21.35 



Our figures are based on analytically pure products. It is evident 

 that Abderhalden missed from 80 to 90 per cent, of the valin which 

 was undoubtedly calculated in with the leucin, as the two are not 

 separable by the methods previously available. Still other prod- 

 ucts in the necessarily crude mixture may account for the high 

 yield from edestin. 



65 (403) 



" Clavin," Vahlen's active principle of ergot. 



By DONALD D. VAN SLYKE. 



\^Froni ihe Rockefeller Institute for Medical Research, Nezv York.'\ 

 In a recent paper Vahlen ^ describes the isolation of the two 

 constituents of clavin, a crystalline substance isolated by him from 

 ergot. By means of their copper salts two substances, leucin and 

 "clavin base" of the formula CjHjjO^N, were separated from the 

 clavin. From analysis of clavin it appeared to consist of leucin 

 and clavin base in molecular proportions, and was regarded as a 

 salt-like combination, similar to that in which some alkaloid bases 

 are found, the leucin acting as acid, the clavin base as base. 

 Vahlen regards clavin as the active principle of ergot in stimulat- 

 ing contraction of the uterus, and the clavin base as the active 

 constituent of clavin. 



From the description of clavin, it appeared similar in both 

 physical and chemical properties to the mixture of leucin and valin 

 obtained from proteins. A sample of Vahlen's clavin was obtained 

 from Merck and submitted to the process devised for determination 

 of leucin, isoleucin, and valin in the presence of one another.^ The 



^Arch.f. exper. Path. u. Pharm., 1909, Ix, 42. 



' Levene and Van Slyke : These Proceedings, 1909, vi, 54. 



