19171 AGRICULTURAL BOTANY. 31 



the transportation of phosphorus to the growing and maturing seeds. The 

 same is thought to be true in the alimentation of the embryo and the nutrition 

 of very young shoots, in which magnesium seems to serve as a vehicle for the 

 transfer of phosphoric acid. Certain observations are thought to indicate the 

 necessity for the pi-esence of magnesium in the shoots in connection with the 

 formation of chlorophyll. 



The influence of various salts on the growth of soy beans, J. W. Shive 

 (Soil Sci., 1 (19 JG), No. 2, pp. 163-170, fig. i).— As a result of experiments to 

 test the influence of various salts on the growth of Glycine hispida and Solanum 

 nigrum, employing the same pots of soil in the same way, it was found that 

 the seeds of the latter failed to germinate and that germination and growth of 

 the former were greatly impaired. These experiments, which are described, 

 are regarded as suggestive but not conclusive. 



Studies in the nutritive relations of our cultivated plants, L. Hiltner, 

 G. Gentner, and K. Maisch {Laiuhv. Jahrb. Bayern, 3 (I'JIS), No. 10, pp. 485- 

 583, figs. 10). — This contains an account of a study by these authors on the 

 growth of plants in nutritive solutions, and of another by the first two authors 

 named on the influence of humus in plant nutrition. 



Diastase activity and invertase activity of bacteria, G. P. Koch {Soil Sci., 

 1 {1916), No. 2, pp. 179-196, figs. 4).— The author states that enzyms deter- 

 mined as diastase and invertase are secreted by bacteria in culture solutions In 

 determinable quantity. Enzyms secreted by bacteria in different solutions 

 show considerable differences in their activity, which also varies from day to 

 day. 



Bacteria appear to produce a factor which may prevent starch hydrolysis and 

 sucrose inversion. There seems to be no direct correlation between hydrolytic 

 enzym secretion and protein decomposition, but a correlation appears to be 

 possible between the utilization of protein decomposition determined as am- 

 monia and the formation of acid. Enzym activity varies considerably with dif- 

 ferent species of bacteria and also with different cultures of the same species. 

 No correlation was found to exist between hydrolytic enzym secretion and the 

 rotation of polarized light, the percentage of reducing compounds, the formation 

 of acid, and the number of organisms. Bacteria may increase or may decrease 

 the rotary power of the solution, but do not produce in the solution a surplus 

 of reducing compounds. There is an increase in bacterial numbers up to the 

 third day, after which Bacillus cold shows irregularity, while Bacterium 

 mycoides shows a decrease. 



Quantitative media for the estimation of bacteria in soils, R. C. Cook 

 {Soil Sci., 1 {1916), No. 2, pp. 153-161). — An account is given of experiments as 

 carried out with different media and soils. 



It is concluded that sodium asparaginate agar, albumin agar, and urea 

 ammonium nitrate agar will usually give a greater colony development than 

 other media now in use for bacteriological work. Albumin agar in which the 

 albumin is dissolved in sodium hydroxid is said to give resalts more consistent 

 than those obtained with albumin in water solution. Considerably higher bac- 

 terial counts were obtained from a five-day than from a three-day incubation 

 period. Equally good results as regards sterilization were obtained from flow- 

 ing steam or steam standing under a pressure of one atmosphere. Difllerentia- 

 tion in blood meal and hay infusion agars w^as marked. The behavior of some 

 soils toward the several media may vary as regards both degree and direction 

 of the influence exerted in the comparative tests. 



A method for the renewal of plant nutrients in sand cultures, A. G. McCall 

 {Ohio Jour. Sci., 16 {1916), No. 3, pp. 101-lOS, fig. i).— The author describes a 

 method which he has devised by which it is claimed that seedlings may be 



