AGRICULTURAL BOTANY. 125 



ployed in the experiments mentioned above. After 24 hours the wheat seed- 

 lings blacken, owing to the fact that they decompose the substances which bind 

 the chromogen in combination and afterwards oxidize it The action is held to 

 be due to the presence of ferments in the seedlings. 



When etiolated leaves of the beans were subjected to autolysis in water the 

 formation of chromogen was noted, this also indicating that it exists in a com- 

 bined state. It is thought that probably the chromogens appear in combination 

 with the ghicosids. This is submittal as a hypothesis, and the author proposes 

 calling the compound " prochromogen." 



The photochemical synthesis of carbohydrates in the absence of chloro- 

 phyll, J. Stoklasa and W. Zdobnicky {Biochem. Ztschr., 30 (1911), No. 6, pp. 

 Ji-J3-Jf5G, pi. 1, fig. 1). — In a previous paper (E. S. R., 24, p. 431) the authors 

 announced the synthetic formation of carbohydrates under the influence of 

 ultraviolet rays and in the absence of chlorophyll. In the present publication a 

 detailed account of their investigations is given. 



The authors found in experiments with ultraviolet rays that there was no 

 formaldehyde nor carbohydrates formed from carbon dioxid and water in the ab- 

 sence of potassium hydroxid. From water vapor and carbon dioxid in the presence 

 of potassium hydroxid, formaldehyde was formed but no carbohydrates. Neither 

 formaldehyde nor carbohydrates were produced from carbon dioxid and non- 

 nascent hydrogen in the presence of potassium hydroxid, and in the absence of 

 the ultraviolet rays formic acid was formed from carbon dioxid and nascent 

 hydrogen in the presence of potassium hydroxid. From carbon dioxid and 

 nascent hj^drogen in the presence of potassium hydroxid sugar was formed under 

 the influence of the ulti-aviolet rays. 



The authors have shown the synthesis of sugars from potassium bicarbonate 

 and nascent hydrogen, and from their investigations they conclude that pure 

 carbonic acid is not reduced in the presence of nascent hydrogen in the chloro- 

 phyll-bearing cell, but that the reduction takes place through the production of 

 potassium bicarbonate formed within the cell. In the presence of this jiotassium 

 the formaldehyde is condensed into carbohydrates. 



Chlorophyll in living chloroplasts, D. I. Ivanovskii (Dnevn. XII. S"Uzda 

 Russ. Est.-Lsp. i Vrach [Moscow], 1910, No. 7, p. 269; ahs. in Zhur. Opytn. 

 Agron. (Russ. Jour. Expt. Landw.), 11 (1910), No. 1, p. 126). — The author 

 notes that the chlorophyll of the living leaf differs from that of an alcoholic or 

 other extract in the position of the absorption bands, in the degree of stability 

 in light and air, and in the dissimilar behavior toward solvents. An investiga- 

 tion is reported on the unequal behavior of the chlorophylls to light and to 

 solvents. 



The experiments led to the conclusion that the hypothesis that chlorophyll 

 in living leaves is constantly destroyed and reformed must be modified, as 

 there appears to be no regeneration of chlorophyll in mature leaves. The 

 stability of the chlorophyll of the living leaf in light and air may be accounted 

 for by assuming that in living chloroplasts the chlorophyll is present in the 

 colloidal state. Experiments have shown that chlorophyll in colloidal solution 

 possesses considerable stability in light and air. This assumption will account 

 for the peculiar behavior of chlorophyll of living leaves to solvents. 



The author believes that possibly it is in the colloidal chlorophyll that the 

 process of decomposition of carbon dioxid takes place. 



The correlation between the osmotic pressure of nutrient solutions and 

 the development and chemical composition of plants, N. K. Maliushchitskii 

 (Dnevn. XII. S"Qzda Russ. Est. Isp. i Vrach [Moscow'], 1910, No. 9, p. 414; 

 abs. in Zhur. Opytn. Agron. (Russ. Jour. Expt. Landw.), 11 (1910), No. 1, pp. 

 122-124). — During the years 1903 to 1907 cereals were grown in sand cultures 



