1919] MOTJLTTJRAL BOTANY. 025 



calcium, and greatly Increased by a deficiency in potassium, phosphi rue, <<r 

 nitrogen. In general, the effects upon the plants of limiting the supply <>f 

 phosphorus or nitrogen are much more noticeable than the effects of limiting 

 the supply of magnesium, calcium, or potassium. 



Direct assimilation of organic carbon by Ceratodon purpureus, W. J. Itmi- 

 bins {Dot. Gaz., 65 (1918), No. 6, pp. 548-551, figs. 5).— The author, presenting 

 results so far as obtained from an Incomplete investigation begun in 191-1 with 

 C. purpureas in pure culture, states that this moss absorbed and utilized or- 

 ganic carbon in the form of levulose, glucose, galactose, lactose, cane BUgar, and 

 maltose; mannite, glycerin, and starch not being utilized. Starch forms in 

 darkness from levulose, glucose, galactose, lactose, cane sugar, and mall 

 Levulose was from two to seven times as effective as a sourse of carbon for 

 growth as glucose, maximum growth occurring with the former in darkness, 

 with the latter in light. Moss plants fceem to require light as well as available 

 carbohydrates for the best development. 



Recent observations on the degradation of inulin and inulids in chicory 

 root, B. Geslin and J. Wolff (Compt. Rend. Acad. Sci. [Paris], 166 (1918). Wo. 

 10, pp. 428-430). — The authors have followed, by means of two ferments dif- 

 fering as regards their mode of action, the changes which occur during the 

 autumn and winter resting period of chicory root in the content of inulin and 

 of the substances which the authors have previously (E. S. R., 38, p. 502) 

 designated by the general term inulids. 



These substances are divided by the authors into two groups according to 

 their effects as regards fermentation and the successive degradations which 

 they undergo, these differences being shown by comparative tests and tabula- 

 tion of results. These results are said to be confirmed by those recently re- 

 ported by Colin (E. S. R., 39, p. 524). 



The sugar content of sorghum at various stages of its growth, D. Ber- 

 thelot and R. Trannoy (Compt. Rend. Acad. Sci. [Paris'], 166 (1918), No. 20, 

 pp. 824-827, fig. 1). — Sorghum saccharatum, studied at Meudon during 1917 in 

 regard to sugar content, showed glucose and levulose earlier than saccharose, 

 the last named reaching its maximum about October 5 and maintaining a 

 somewhat lower level during the latter half of November, and the other two 

 decreasing from about August 24 to November 16 but showing a slight rise 

 during the rest of that month. 



Development of the principal sugars of sorghum and the effect of castra- 

 tion, D. Berthelot and R. Tuannoy (Compt. Rend. Acad. Sci. [Paris], 166 

 (1918), No. 22, pp. 901-910, fig. 1). — Having studied the history of sugars at an 

 earlier period than that of the work noted above, the authors found that sac- 

 charose followed the same general course as in the previous study, castration 

 making no apparent difference in the saccharin content. Comparisons are made 

 between sorghum and beets as sugar-producing plants in regard to economic 

 and other phases. 



Chemical changes accompanying abscission in Coleus blumei. H. C. S 

 sox (Bot. Gaz., 66 (1918), No. i, pp. 82-58). — Giving an account of studies on 

 C. blumei and of methods employed, with discussion, the author states that 

 abscission in C. blumei results from conversion of cellulose into pectose. Tins 

 is further transformed into pectic acid and pectin, leading to an excess amount 

 of pectic acid over that of the available calcium sufficient to maintain the 

 solidity of the middle lamella of the cell walls of the abscission layer. These 

 processes are possibly initiated and probably accelerated by the presence of 

 oxidases and ferric ions, both of which accumulate in the abscission layer. 



Metachromatin and phenol compounds in the vegetable cell, A. Guii.i.iei:- 

 mond (Compt. Rend. Acad. Sci. [Paris], 166 (1918), No. 2S, pp. 958-960).— It is 



