176 PHYSIOLOGY [Bot. Absts. 



1223. Jacobsen, C. A. Alfalfa saponin. Alfalfa investigation VII. Jour. Amer. Chem. 

 Soc. 41 : 640-648. 1919. — Alfalfa saponin has the empirical formula C27H37NO16. It hydro- 

 lyzes to a sapogenin and glucose. Each molecule of saponin has one pentose radical. In the 

 case of fish the alfalfa saponin acts in an asphyxiating manner; otherwise it is not poisonous, 

 except when injected subcutaneously. Then it causes local irritation and death. Alfalfa 

 saponin is readily soluble in water and warm glycerine. It is slightly soluble in hot 95 per 

 cent alcohol and in glacial acetic acid, very slightly in ethyl acetate, carbon tetrachloride, 

 phenol, nitro-benzine, and methyl alcohol. It is insoluble or nearly so in cold 95 per cent 

 alcohol, ether, chloroform, benzine, and amyl alcohol. — J. M. Brannon. 



1224. Monroe, K. P. The preparation of xylose from corn cobs. Jour. Amer. Chem. Soc. 

 41 : 1002-1004. 1919. — The method here described had for its object the removal of the adhe- 

 sive gum by a more convenient laboratory method than extraction in an autoclave at 160°C. 

 The gum is removed by digestion with dilute alkali at 100°. — J. M. Brannon. 



1225. Nelson, E. K. The constitution of capsaicin, the pungent principle of Capsicum. 

 Jour. Amer. Chem. Soc. 41: 1115-1122. 1919. 



1226. Nelson, J. M., and Frank M. Beegle. Mutarotation of glucose and fructose. 

 Jour. Amer. Chem. Soc. 41: 559-575. 1919. 



1227. Shibata, Keita, Yuji Shibata, and Itizo Kasiwagi. Studies on Anthocyanins : 

 Color variation in anthocyanins. Jour. Amer. Chem. Soc. 41: 208-220. 1919. 



1228. Smith, C. R. The mutarotation of gelatin and its significance in gelation. Jour. 

 Amer. Chem. Soc. 41: 135-150. 1919. 



METABOLISM (ENZYMES, FERMENTATION) 



1229. Davis, Lewis, and Harvey M. Merker. Studies on pepsin. I. Chemical changes 

 in the purification of pepsin. Jour. Amer. Chem. Soc. 41 : 221-228. 1919. — The purification 

 of pepsin seems to consist in the elimination of secondary proteins including a-amino acids. 

 Calcium and sulfur seem to be unaltered as a result of purification, but phosphorus is mate- 

 rially reduced. "Chlorides are seemingly removed." The optical activity appears unchanged. 

 — J. M. Brannon. 



1230. Higgins, B. B. Gum formation with special reference to cankers and decays of 

 woody plants. Georgia Agric. Exp. Sta. Bull. 127: 21-60. PL 1-6, fig. 1-15. Jan., 1919.— 

 Assuming that gummosis is probably brought about by the action of an enzyme whose forma- 

 tion from a zymogen might be induced by many forms of excitation, several attempts were 

 made to isolate a pectin-dissolving enzyme from gumming wood, but without success. Gum- 

 mosis in relation to temperature was studied on various species of Prunus, Prunus mahaleb 

 L. being mainly used. Employing twigs under various conditions it is shown that gum for- 

 mation is initiated by slight drying and that bud and callus growth will not start in a saturated 

 atmosphere. With twigs it was experimentally determined that the minimum temperature 

 at which perceptible gum formation occurs is near 10°C, optimum and maximum tempera- 

 tures not being ascertained. Gumming in relation to chemical poisons was studied by intro- 

 ducing small quantities of HgCl 2 , CuS0 4 , and (NH 4 ) 2 S04 under the bark of various species 

 of Prunus and covering the wounds with grafting wax. After seventeen days no killing of 

 the tissues was noted around the (NH 4 ) 2 S04. The HgCl 2 and C11SO4 induced gum formation 

 around the wounds in forty-eight hours. The bark of the branches was killed from 15 to 60 

 cm. above the wound and to 2.5 cm. below, while the wood was killed to a greater distance 

 with a dark deposit of gum at the lateral limits. Twigs of Prunus persica placed in diluted 

 solutions of HgCl 2 from 1-500 to 1-1,000,000 showed gumming in dilutions of 1-500,000. Ex- 

 periments on dormant trees showed that active growth is not essential for gum formation. 

 For studying microtome sections the ruthenium red-methyl green combination stained the 



