THE ROTARY PROPERTIES OF SOME 

 VEGETABLE PROTEIDS.* 



Br ARTHUR C. ALEXANDER. 



I. INTRODUCTORY. 



So far as the writer has been able to ascertain, no reliable 

 determinations have ever been made of the rotary properties 

 of any of the vegetable proteids, although some of them can 

 now be obtained in a pure state and in considerable quantities. 

 The object of this investigation was to determine accurately 

 the rotary power of some of the crystallized vegetable proteids. 

 The globulin found hi hemp seed was chosen as the main 

 subject of study, because it could be obtained in a perfectly 

 crystalline form with comparative ease. For purposes of 

 comparison, the rotary powers of the crystallized globulins 

 obtained from flaxseed and the Brazil nut were also deter- 

 mined under similar conditions. The identity of each of these 

 three proteids has been completely established by the researches 

 of Osborne,f Chittenden and Mendel,^ and others, and a 

 guarantee of chemical purity is furnished in their crystalline 

 form. Their individual compositions and properties will be 

 described later in connection with the results of the polarimeter 

 observations. 



A complete determination of the rotary properties of any 

 substance should include a study of the effect on its rotary 

 power of three factors (1) the solvent used; (2) the con- 

 centration of the solution ; (3) its temperature. The proteids 

 investigated by the writer were imperfectly soluble in most 

 solvents at the temperature of the room, and their solutions 



Reprinted from the Journal of Experimental Medicine,' vol. L 

 t American Chemical Journal, vol. xiv, pp. 629, 662. 

 J Journal of Physiology, vol. xvii, p. 60. 



