AGRICULTURAL BOTANY, CHEMISTRY AND PHYSIOI.OGY OF PI^ANTS 1 257 



does not fix atmospheric nitrogen. In its presence it fixes nitrogen in 

 appreciable quantities. The optimum degree of concentration of the 

 catalyser is the same as for B. radicicola (0.0041 gr. of nitrogen per 100 

 cc. of culture bouillon were fixed with this amount) ; in concentrations 

 higher than the optimum, the acceleration is diminished and finally 

 becomes negative. 



The experiments with A~o!obacler chroococciim yielded results similar 

 to the preceding ones. This bacterium likewise only fixes atmosplieric 

 nitrogen in the presence of manganese ; the optinumi concentration of 

 tlie manganese ion is about the same. 



The practical conclusion is that fertilisers containing manganese in- 

 crease the crop, if applied in quantities furnishing up to 0.006 gr. of man- 

 ganese ion per 100 gr. of soil. They reduce it if administered in quantities 

 in excess of this. The majority' of soil contain quantities of manganese in 

 excess of the above optinuim, but the bulk of this manganese is in insoluble 

 form. In order to calculate the quantity of manganese salt to be put 

 down as manure, therefore, it is first necessary to ascertain the quantity 

 of soluble manganese contained in the soil and add only the difference. 



963 - Successful Treatment with Insecticides of Plants in Flower. — Shreiber a. f., in 



Tpifd hi Bx)po no npuKJaOHoii BowaHiuc^o {BitUdin of Applied Botany), IXth Year, 



No. 4 (8g), pp. 174-175. Petrograd, April 1916. 



After referring to the experiments by Prof. S. Glasenap, on the success- 

 ful treatment wdtli tobacco juice of apple trees in flower (i), the writer gives 

 the results of his own experiments at Irkutsk (vSiberia) on an experimental 

 field for the cultivation of medicinal plants. 



The experiments were carried out on Calendula officinalis ly. which is 

 ver\' liable to the attack of the larvae of Mamesira hrassicae, these latter 

 devouring the leaves. One part of the plants in the field was sprayed with 

 dilute extract of aloes and the other part with a solution of extract of Vera- 

 truni album. Two successive sprayings were made which killed oft" all the 

 larvae. This treatment did not reduce the crop of seeds, and the plants 

 watered in this way when in flower all ^-ielded ripe seeds. 



964 - Osmotic Pressure of Soil Moisture and Classiness of the Grain of " Bielotourka" 



Wheat. (From the Works of the I.aboratory and Growing Shed of the Scientific Agricul- 

 tural Station of Bezentchouk, Province of Samara, Russia). — ToulaikovN., in }K//p- 

 najo Onbimnou AjponoJllu (Review of Experimental Agriculture), Vol. XVII, Book I, 

 pp. 79-91. Petrograd, 191 6. 



Great fluctuations in the price of hard wheat, which took place on one 

 and the same day at the Exchange of Samara, attracted the attention of 

 the vStation, which, from 1913 onwards, organised a series of experiments on 

 the glassiness of the grain of the " Bielotourka " hard wheat, thus continu- 

 ing work on the relations between the osmotic pressure of the soil moisture 

 and the growth of the wheat in question (2). 



AGRICULTURAL 



BOTANY. 



CHEMISTRY 



AND 

 PHYSIOLOGY 

 OF PLANTS. 



(i) See Bulletin dc Botaniqiie appliqiiee, Vol. VI, No. 4, pp. 243-247 ; Petrograd, 1915. 



(Ed.) 

 (2) See B. 1914, No. 980. (Ed.) 



