NOTES AND ABSTRACTS. 



Mesembryanthemum simulans. By N. E. Brown {Gard. Chron. Oct. 12, iqi8, 

 p. 145 . with fig.). — Records the punctuality of the daily opening and closing 

 of flowers, and provides the first complete description in English. — E.A.B. 



Myrsine africana Linn. By N. E. Brown (Bot. Mag. t. 8712 ; May 191 7). — 

 A native of Africa, India, and China. A hardy evergreen shrub, very orna- 

 mental when in fruit. It is, however, strictly dioecious, and unless both sexes 

 are grown, the beauty of the female plant when in fruit will not be realized. 

 The fruit is a shining globose berry, violet purple. — L. C. E. 



Nicotine on Sprayed Plants, Kow to test for the Presence of. By V. I. Safro 

 (Jour. Econ. Entom. vol. x. pp. 459-461, Oct. 1917). — The author states the 

 general belief that as soon as a nicotine spray dries on the leaf it disappears, and 

 proceeds to detail a test which shows this assumption to be incorrect. The test 

 consists in taking a number of leaves which have been sprayed and thoroughly 

 rinsing them in a minimum of distilled water. In some of the tests, where five 

 leaves gave a doubtful reaction, ten leaves gave a definite one ; but as a rule 

 five leaves in 25 c.c. of water showed a definite indication of the presence of 

 nicotine, where the usual spray strength had been used. After having rinsed 

 thoroughly, filter and make filtrate slightly acid with a few drops of hydrochloric 

 acid. If a precipitate is formed at this point filter again. To filtrate add several 

 drops of 1 per cent, silicotungstic acid. A white cloudiness denotes presence of 

 nicotine. It is not stated how long after spraying the tests were made. 



G. W. G. 



Nitrate-Nitrogen, some Factors affecting its Accumulation in Soil. By P. L. 



Gainey and L. F. Metzler (Jour. Agr. Res. xi. pp. 43-64, Oct. 1917). — The 

 authors show that the aeration in uncultivated soil is far in excess of that 

 necessary to maintain aerobic conditions. They conclude that some factor 

 other than increased aeration is at work in promoting nitrification in cultivated 

 soils. — F. J. C. 



Nitrifying Bacteria, The Effects of, on Solubility of Calcium Phosphate. By 

 W. P. Kelley (Jour. Agr. Res. xii. March 1918, pp. 671-683). — The author 

 finds that the addition of CaCO s produced no immediate effect on the solubility 

 of soil calcium or that added as calcium phosphate. No increase in the solubility 

 in water of the soil phosphates or of calcium phosphate was produced by bacterial 

 action, except in the nitrification of ammonium sulphate when added without 

 calcium phosphate. The addition of calcium carbonate brought about an increase 

 in soluble calcium, but tended to lower the solubility of calcium phosphate. 

 Calcium carbonate also promoted more active nitrification than calcium 

 phosphate. 



A short bibliography is appended. — A. B. 



Nitrogen-assimilating Bacteria, Influence of Nitrates upon. By T. L. Hills 

 (Jour. Agr. Res. xii. Jan. 1918, pp. 183-230). — The general conclusions were : 

 Small quantities of potassium, sodium, and calcium nitrates caused a great 

 increase in the number of Azotobacter in sterilized soils. Ammonium nitrate in 

 the same quantities caused a less-marked increase. Higher concentrations were 

 not so favourable to the growth of the organisms. 



Potassium and sodium nitrates caused an increase in amount of nitrogen 

 assimilated by the Azotobacter on agar films. Calcium nitrate in the same 

 amounts brought about a decrease in the amount of nitrogen fixed to a point 

 even below that representing the amount assimilated in the absence of nitrates. 

 In soil cultures, sodium and calcium nitrates caused an increase in total nitrogen, 

 which was more marked in the unsterilized cultures than in those cultures 

 sterilized and inoculated with a pure culture of Azotobacter. 



Under aerobic conditions Azotobacter in liquid cultures reduced nitrate to 

 nitrite but not to ammonia. More atmospheric nitrogen was assimilated in the 

 presence of nitrate than in the absence of this salt. 



The number of Bacillus radicicola in sterilized soil was increased by addition 

 of small quantities of potassium, sodium, ammonium, and calcium nitrates. This 

 increase was not so marked as in the Azotobacter cultures. B. radicicola appeared 

 much more resistant to higher concentrations of nitrates than Azotobacter. In 

 liquid cultures, all three nitrates caused a large increase in the amount of gum 

 obtained by precipitation with acetone. 



Large quantities of nitrates proved detrimental to the formation of nodules 

 on alfalfa. The plants grown in presence of large amounts of nitrate did not 

 produce nodules when inoculated with a viable culture of B. radicicola. Nitrates in 

 soil cultures prevented the re formation of nodules once removed and also caused 

 a decrease in number of nodules already present. 



A good bibliography is appended. — A . B. 



