AGRICULTURAL BOTANY. 727 



A series of experiments was conducted in which standardized castor beau 

 leaves and tomato plants were sprayed with Bordeaux mixture, aluminum mix- 

 ture, lime, and certain other tilm-forming liquids and powders. In every case 

 the rate of transpiration was hij,'her in the Bordeaux sprayed plants than in 

 the controls. The important differences observed malie it necessary to give 

 weight to increased transpiration in any explanation that is offered concerning 

 the stimulating effect of Bordeaux mixture. 



Belation of certain grass-green alg-ae to elementary nitrogen, J. R. Schramm 

 (Abs. in Science, n. ser., SO {1914), No. 908, pp. 260, 261).— The author states 

 that the number of species of algae, in which the free nitrogen fixation has been 

 Investigated under pure culture conditions, is relatively small, not more than 

 4 or 5 genera having been so studied. 



By a variety of methods 25 si)ecies were isolated as pure cultures, 2 of them 

 being blue-green algie, 2 diatoms, and the remainder grass-green algie. Seven 

 species of the latter were tested for nitrogen fixation in the complete absence 

 of combined nitrogen. At the same time the effect of the slightly elevated tem- 

 perature was determined in a duplicate series of experiments. No fixation of 

 nitrogen was observed in any of the species and, unlike certain fungi, no favor- 

 able effect was exercised by the higher temperature. 



Metabolism of the nitrogen in Aspergillus niger, PI. J. Waterman (K. 

 Akad. Wetensch. Amsterdam, Proc. Sect. Sci., 15 {1013), pt. 2, pp. 1047-1057, 

 fig. 1; abs. in Jour. Ghem. Soc. [London], 104 {1013), No. 610, I, p. 045). — The 

 author summarizes the findings of this study substantially as follows: 



The ratio of the nitrogen fixed to the carbon assimilated in A. nigcr lowered 

 with time, becoming constant in the mature mold. The rapidity of the metab- 

 olism is subject to great changes, that of nitrogen resembling closely that of 

 carbon as regards factors concerned in their production and rate of change. 

 Metabolism of nitrogen is but little influenced by substitution of rubidium for 

 potassium and is independent of the nitrogen source. No fixation of atmos- 

 pheric nitrogen was observed. 



Metabolism of the phosphorus in Aspergillus niger, H. J. Waterman {K. 

 Akad. Wetensch. Amsterdam, Proc. Sect. Sci., 15 {1013), pt. 2, pp. 1058-1063). — 

 In addition to having shown (see above) that the metabolism of nitrogen In 

 A. niger is analogous to that of carbon, the author further claims to have found 

 that phosphorus behaves in much the same manner as do those two elements. 

 It is held, further, that the quantities of the elements present in the mature 

 mold do not correspond to the quantities really active during development, also 

 that the same quantity of an element may be several times active in metabolism, 

 one cell taking up the products given out by another. 



Potassium, sulphur, and magnesium in the metabolism of Aspergillus 

 niger, H. J. Waterman {K. Akad. Wetensch. Amsterdam, Proc. Sect. Set., 15 

 {1013), pt. 2, pp. 1340-1355) .—Referrmg to the reports above noted, the author 

 states that like carbon, nitrogen, and phosphorus, the sulphur is accumulated in 

 the cell and afterwards partly excreted. In the physiological action of potas- 

 sium two functions are to be distinguished, one corresponding with that of 

 rubidium, the other with that of manganese. oNLagnesium differs from the other 

 required elements in that strong concentrations and some time are required 

 to produce any considerable growth therewith. It is thought that magnesium 

 may act by counteracting some as yet unknown noxious factor present. Zinc 

 can replace magnesium in the culture media, but the same is not true of beryl- 

 lium, lithium, manganese, and calcium. No action by cadmium, strontium, and 

 mercury analogous to that of zinc in this respect has yet become evident. 

 Extremely slight quantities of zinc are suflicient to activate magnesium. 



