30 EXPERIMENT STATIOl^ RECOED. 



contain proteases which digest vegetable fibrin and produce tryptophane from 

 albumoses and peptones. 



The occurrence of rennet in plants, C Gerber (Rev. Sci., -'fS {1910), I, 

 No. 7, PI). 195-207). — A critical review is given of literature relating to the 

 occurrence of rennets in plants, their localization, effect of vegetable rennets 

 on milk, relation between rennets and the proteolytic ferments of plants, etc., 

 after which the role of rennets in plants is discussed. The author claims that 

 they play an important part in synthesis, in translocation and the storing of 

 reserve proteid material, and in the conduction and nutrition of the pollen 

 tube from the stigma to the ovule. 



Inoculation experiments with red clover and serradella, B. Steglich 

 {Jahreshcr. Landic. Konigr. Sachs., 190S, p. 120). — Experiments with red clover 

 and sei'radella were conducted to determine, if possible, the reason for the lack 

 of success when serradella follows red clover in crop rotation. It was found 

 by inoculation experiments that the poor growth of the serradella was (\ne to 

 the injurious action of the clover tubercle bacteria on the serradella. 



Remarks on the formation and consumption of nitrous oxid by bacteria, 

 B. Tacke (CrnthJ. Bali, [(ic.^. 2. Aht., 20 (1910). Xo. 6-7. p. 230).— Thin is a 

 criticism of the investigations reported by Beijerinck and Minkmann (E. S. R., 

 22, p. 724). The author claims to have previously shown in an article published 

 in 1SS7 that nitrous oxid was produced by denitrifying bacteria, and also that 

 nitric oxid was developed from fermenting turnips in a vacuum. After 8 to 10 

 days it was present in sufficient quantities to form red fumes of nitrogen 

 peroxid when air was admitted to the vessel. 



The employment of cellulose as a source of energ'y for the assimilation 

 of atmospheric nitrog'en, H. Pringsheim (CenthJ. Balct. [c^c], 2. Aht., 23 

 (1909), Xo. 10-13. pp. 300-30 .'i; 26. {1910), No. 6-7, pp. 222-227).— This is a 

 discussion of further investigations (E. S. R., IS, p. 324: 20, p. 18) on nitrogen- 

 fixing bacteria and the various sources of energy available in the assimilation 

 of free nitrogen in the soil. 



It is shown that by the association of nitrogen-assimilating Clostridia and 

 cellulose-disintegrating bacteria, the insoluble carbohydrate materials in the 

 form of cellulose, which is unavailable to the Clostridia alone, are made avail- 

 able, thus providing a symbiosis between these two groups of soil bacteria. It 

 is further shown that for the utilization of insoluble carbohydrates, the asso- 

 ciation of anaerobic bacteria, as Clostridia and cellulose-fermenting bacteria, 

 is better than the association of the aerobic Azotobacter and an anaerobic cel- 

 lulose-fermenting bacteria ; also that in such combinations the cellulose is 

 capable of supplying more energy to the nitrogen-assimilating micro-organisms 

 than the more soluble carbohydrates, like cane, grape sugar, milk sugar, starch, 

 and mannite. 



The utilization of the cellulose as a source of energy follows the rule pre- 

 viously laid own for other carbohydrates, that a low concentration of about 0.5 

 per cent is the best. As a result of these investigations, it is claimed that the 

 presence in the soil of decaying organic matter is of great value in furnishing 

 an avai]al)le source of energy to nitrogen-assimilating bacteria. 



The assimilation of carbon dioxid by hydrogen-oxidizing bacteria, A. J. 

 Lebedeff {Bcr. Deut. Bat. GeselL, 27 {1910), No. 10. pp. 598-602).— The results 

 are given of a number of experiments conducted by the author, which show that 

 an energetic process independent of the assimilation of the carbon dioxid oc- 

 curs which is exactly represented by the equation 2H2+02=2H:;0. Further, 

 by the autotropic assimilation of carbon dioxid by the hydrogen-oxidizing bac- 

 teria, a decomijosition of the carbon dioxid is produced, with the simultaneous 

 liberation of equal volumes of oxygen, the same as iu green plants. The 



