AGRICULTURAL BOTANY. 623 



iient attained by peas furnished with distilled water with that attained by 

 hose furnished with aerated water is said to support the hypothesis that sub- 

 stances are formed by growing roots which are toxic to plants of the same 

 species. 



The root nodules of the Podocarpese, W. B. Bottomley (Abs. in Rpt. Brit, 

 Assoc. Adv. Sc-L, 1912, p. 67^).— Discussing the functions of the root nodules of 

 the several genera in connection with their structure as described by Miss Ethel 

 R. Spratt (E. S. R., 27, p. 828), the author states that the bacterial tissue of 

 the nodule continues functional as such for one year only, being pushed out in 

 the following spring to form in connection with older layers an outer pro- 

 tective zone, the outermost layer of which remains intact except in case of the 

 bifurcated nodules of Saxegothsea. 



The function of calcium in plants, K. Faack {Mitt. Landw. Lehrkanz. 

 K. K. HochscJi. Bodenkul. Wien, 2 {1913), No. 1, pp. i75-207).— Presenting the 

 results of a study on the influence of calcium and related elements separately 

 and together on plants, the author states that the injurious effects of a calcium- 

 free medium are due to its extraction of calcium from the plant organs, which 

 by inner supply with calcium may be protected from such injury; that high 

 concentrations of strontium without calcium influence plant growth unfavorably ; 

 that by supplying sufficient calcium with strontium the injurious effects of the 

 latter are lessened or prevented ; that while strontium in part takes the place 

 of calcium, permitting limited development, its influence is partial and tem- 

 porary, only deferring the exhaustion of the plant; and that strontium does 

 not appear to influence the distribution of carbohydrates or the localization of 

 that process. A bibliography is appended. 



The inutility of zinc in the culture of Aspergillus niger, C. Lepiebre 

 {Compt. Rend. Acad. Set. [Paris}, 157 {1913), No. 19, pp. 876-879).— In con- 

 tinuance of previous reports (E. S. R., 29, p. 628), the author states that while 

 under certain conditions zinc exerts a favorable influence on growth of A. 

 niger, its presence is not indispensable to the complete development of this 

 fungus. Apparent exceptions are probably due to a lacli of purity in the ma- 

 terials employed. 



Inutility of zinc for culture of Aspergillus niger, C. Lepierre {Bui. Soc. 

 Chim. France, 4. ser., 13 {1913), No. 24, PP- 1107-1121).— Contmuing the above 

 discussion of his own work, in connection with the results and views of others, 

 the author holds that the undeniable utility of zinc in certain concentrations 

 for the culture of A. niger is not to be confounded with the indispensability 

 thereof, as held by some authors mentioned. 



Zinc and Sterigmatocystis nigra, H. Coupin {Compt. Rend. Acad. Sci. 

 [Pans], 157 {1913), No. 25, pp. 1^75, 1^76). —Noting recent observations of his 

 own in connection with the reports and views of Lepierre (see above), con- 

 sidered by Javillier to be inconsistent with the results of his own experiments 

 (E. S. R., 20, pp. 28, 831), the author concludes that the results of his own work 

 and that of the former author are reciprocally confirmatory. 



Zinc and Aspergillus, C. Lepierre {Compt. Rend. Acad. Sci. [Pans], 158 

 {1914), ^^0. 1, pp. 67-70; abs. in Rev. Sci. [Paris], 52 {1914), I, No. 3, p. 94)-— 

 Repeating the experiments of Coupin and Javillier (above noted) under the 

 original conditions, so far as possible, the author concludes that the differences 

 noted, which were apparent also in his experiments, may be due to differences in 

 conditions of aeration, etc. 



Osmotic pressures in plant organs. — III, The osmotic pressure and elec- 

 trical conductivity of yeast, beer, and wort, H. H. Dixon and W. R. Q. 



38196°— No. 6—14 3 



