AGRICULTURAL BOTANY. 129 



All plants having milky latex except M. clastica were shown to be subject to 

 attack by snails, this result tending to invalidate the claim that the presence 

 of milky sap or caoutchouc in the leaves is protective against these animals. 



The microchem^ical recognition and the distribution of aluminum in. 

 plants, E. Kratzmann (Sitzher. K. Akad. Wiss. [Vienna], Math. Naturiv. Kl., 

 122 (1913), II, No. 2, pp. 311-236, figs. 6; abs. in Rev. Set. [Paris], 52 (1914), 

 I, No. 12, pp. 369, 310). — The author has made a study of the occurrence of 

 aluminum in plant tissues by microchemical methods based upon the formation 

 of the double sulphate of caesium and aluminum. He examined several hundred 

 plants representing many families and found that aluminum is present quite 

 extensively in the plant kingdom, certain species being extremely rich in that 

 substance. There did not appear to be any connection between the aluminum 

 content of the plant and the botanical relationship of the species, for notable 

 variations wei'e noticed in diffei'ent specimens of the same genus and species. 

 In certain cryptogams aluminum was found concentrated in the foliar lobes 

 carrying the spore bearing organs, and the content in flowers was foimd in 

 some instances greater than that in other parts of the plant. 



Some effects of colloidal metals on Spirogyra, W. D. Hoyt (Bot. Gaz., 51 

 (1914), No. 3, pp. 193-212, figs. 4).— From the author's account of studies as 

 detailed, it may be stated that colloidal silver, though injurious to Spirogyra 

 when used alone even in weak concentrations, was rendered less so by addition 

 of colloidal platinum, animal charcoal, or inorganic salts. Colloidal gold with 

 sodium hydrate was only slightly injurious. Colloidal platinum, almost harm- 

 less itself, partially corrected the toxicity of tap water, distilled water, and 

 solutions of potassium chlorid, magnesium sulphate, and colloidal silver. Toxic 

 solutions of sodium hydrate were rendered less so by colloidal gold, platinum, 

 and silver, but not by gold chlorid. 



Filaments of Spirogyra, originally from the "same culture but grown for a 

 time in different media, exhibited different reactions in the solutions of colloidal 

 gold and sodium hydrate as well as in the other toxic solutions employed. 



A bibliography is appended. 



Influence of radio-activity on. plants, L. Malpeaux (Yie Agr. et Rurale, S 

 (1914), ^^0. 11, pp. 289-293, figs. 3).— A report is given of the effect of a 

 fertilizer material that is claimed to have radio-active properties on the growth 

 of rye grass, oats, turnips, sugar beets, fodder beets, and potatoes, comparisons 

 being made with the same plants grown with and without complete fertilizers. 

 The plants subjected to the radio-active substance appeared to be stimulated to 

 some extent and were darker green in color, but the yields were but little if 

 any greater than where a complete fertilizer was used. In case of the root 

 crops, there was apparently some increase in the sugar content, which it was 

 thought could be attributed to the radio-active substance. 



Penetrative power of violet and ultraviolet rays in regard to leaves, P. A. 

 Dangeard (Compt. Rend. Acad. Sci. [Paris], 158 (1914), No. 5, pp. 369, 370).— 

 Reporting a study on the penetrability of foliage of several species of plants, 

 the author shows that the various species can be arranged in classes differing 

 in this respect, some being much more readily penetrable by the shorter wave 

 lengths than is glass of corresponding thickness. It is thought that the facts 

 observed may furnish a new point of departure for a study of the nature and 

 cause of differences occurring in leaves. 



Axial abscission in Impatiens sultani as the result of traumatic stimuli, 

 R. A. GORTNER and J. A. Harris (Amer. Jour. Bat., 1 (1914), No. 1, pp. 48-50). — 

 The authors describe an abscission in I. sultani as the result of injury due to 

 greenhouse pests, the removal from a shaded room and transplanting out of 



