AGRICULTURAL BOTANY. 227 



majority of molds, and adouite by only a few. All 3 of the bexntomic alcohols 

 may be considered good sources of carbon. 



The influence of starch, peptone, and sugars on the toxicity of various 

 nitrates to Monilia sitophila, O. Kunkel {Bui. Torrcy Bot. Cluh, 40 {19 IS), 

 No. 11, pp. 625-639). — Studies were made to determine whether or not the 

 toxicity of various salts to M. sitophila is influenced by sugars, starch, or pep- 

 tones. 



The results show beyond question that the concentration at which the various 

 inorganic salts are toxic depends on the kind of organic substance contained in 

 the media to which those salts are added. The degree of toxicity of the nitrates 

 of barium, aluminum, iron, and urea depends on the organic substance con- 

 tained in the medigi in which these salts are offered. Barium nitrate is more 

 toxic in peptone than in starch media, while iron and aluminum nitrates are 

 more toxic in starch than in peptone media. The toxicity of iron nitrate is ap- 

 proximately the same in starch as in other carbohydrates, but it is much less 

 toxic in peptone media. Urea nitrate was found to be four times more toxic 

 in starch than in peptone media. 



On the effect of chloroform on the- respiratory exchang-es of leaves, D. 

 Thoday {Attn. Bot. ILondon], 21 {1913), No. 108, pp. 697-717, figs. 7.5).— The 

 author made a study to determine whether a close quantitative relation exists 

 between the evolution of carbon dioxid and the absorption of oxygen under the 

 influence of stimulating agencies. Sunflower, garden nasturtium, cherry laurel, 

 etc.. were subjected to the effect of chloroform, and in all the leaves examined 

 treatment with a small dose of chloroform resulted in a stimulation of the 

 respiration, and the absorption of oxygen and production of carbon dioxid ap- 

 parently remained coordinated. When the concentration of chlorofrom vapor 

 was large enough to bring about visible disorganization, the production of carbon 

 dioxid was diminished and the absorption of oxygen was no longer closely cor- 

 related with the production of carbon dioxid. 



In leaves of the nasturtium {Tropwolu-m ma jus), which contain no tannin, the 

 absorption of oxygen was depressed still more than the production of carbon 

 dioxid. In leaves of other species containing tannin the absorption of oxygen 

 was very rapid for a short time, and though falling quickly, remained at a 

 higher level than the production of carbon dioxid. 



Tannin and starch in the assimilating organs of Leguminosse, H. Klenke 

 {Ueber das Vorkommen von Gerhstoff und Starke in den Assimilationsorganen 

 der Leguminosen. Diss., Gottingen, 1912, pp. 88; abs. in Bot. Centbl., 122 {1913), 

 No. 18, pp. 44^» H7). — As a result of studies on 208 different species of Legu- 

 minosre, the author concludes that tannin is usually more plentiful in leaves or 

 parts more exposed to sunshine, especially in summer, reaching a maximum 

 for the leaves in the vascular bundles and the leaf edges. The stomatal cells 

 vary in this respect less than do neighboring cells. The concentration of tannin 

 is said, however, to be greater in the petiole and shoot than in the leaf. Cells 

 without tannin have more starch than do those containing tannin. 



The castor bean plant and laboratory air, E, M. Harvey {Bot. Gaz., 56 

 {1913), No. 5, pp. Jf39-JfJi2). — The author reports having found potted seedlings 

 of castor bean, grown under ordinary greenhouse conditions until they had 

 developed from 5 to 7 leaves, were unusually susceptible to gas impurities. 

 One part of ethylene to 50,000 of air was found to result in proliferation and 

 exudation at leaf scars. Leaf fall took place in concentrations as low as 1 part 

 of ethylene to 500.000 of air, or even to 1.000.000 parts of air. A drooping of the 

 youngest well-developed leaves could be taken as an index of the occurrence 

 of still lower concentrations of the gas. 



