530 EXPERIMENT STATION EECORD. 



logical tests, and tlien in these solutions wheat seedlings from 4 to 5 cm. high 

 were grown for 15 days under greenhouse conditions of uniform temperature 

 and light. The growth of the wheat seedlings in the various cultures was 

 measured by the transpiration relative to the control cultures, and the water 

 loss was reported every fifth day. It is claimed that when the bacteria are 

 omitted from the sterilized solutions no evidence of toxicity is noticeable for 

 the wheat seedlings, but that when grown in the inoculated culture media ihere 

 Is an active stimulation or depression of the normal functions of the plants. 



Experiments are also reported on the ability of micro-organisms to convert 

 soluble proteids into amido-acids and allied products from the decomposition 

 of proteids, in which sterilized solutions of bog water and peat were used as 

 culture media to which sufficient peptone was added to produce a 1 per cent 

 peptone culture. The cultures were tested physiologically after a 2-weeks 

 incubation by growing wheat seedlings in them for 5 days, at the end of which 

 time transpiration, growth, and the green and dry weight of the plants were 

 found to be proportionately reduced. 



It is claimed that the retardation in growth of the wheat plants is not caused 

 by physical or chemical conditions, but through the direct activity of the bac- 

 terial flora, and that reciprocal relations may exist between groups of soil 

 bacteria and the plants grown upon the soil. The injury to cultivated crops by 

 weeds or previous crops may be due to influences on the bacterial life of the 

 soil unfavorable to succeeding agricultural crops. 



The decomposition of uric acid by bacteria, F. Liebert {E. Akad. Wetensch. 

 Amsterdam, VcrsL Wis en Natuurk. Afdcel, 17 {1908-9), pt. 2, pp. 990-1001, 

 pi. 1; K. Akad. Wetensch. Amsterdam, Proc. Sect. Sci., 12 (1909-10), pt. 1, 

 pp. 5Jf-6Ji, 1)1. 1; abs. in Bot. Ccnfbl., 114 {1910), No. 1.',, pp. 361, 362).— It was 

 found that in the decomposition of uric acid by aerobic bacteria the acid was 

 broken up into carbon dioxid, ammonia, and the intermediate products allan- 

 toin, urea, and oxalic acid. 



These bacteria belong to two groups, viz, those which flourish in slightly acid 

 or neutral media, such as Bacillus fluorescens liqucfacicns, B. fluorescens non- 

 liquefaoiens, and Bacterium calco-aceticum, and those which grow only in 

 alkaline media, such as Bacterium odoratnm n. sp. and Urobacillus muscuU 

 n. sp. When the uric acid forms the carbon source for the bacteria, tlien 

 Bacillus pyocyancus and B. stutzeri in the presence of nitrate of soda produce 

 denitrification. In complete anaerobic cultures the uric acid was decomposed 

 by B. acidi urici n. sp., a spore-forming motile obligate anaerobe which splits 

 the acid into carbon dioxid, ammonia, and acetic acid. 



The mobilization of the phosphoric acid in soils under the influence of 

 bacterial activity, S. A. Sewerin {Genthl. Bakt. [etc.], 2. AM., 28 {1910), No. 

 22-24, pp. 561-5S0). — The results are given of experiments in bouillon flask 

 cultures to which tricalcium phosphate had been added, on the changes in 

 phosphoric acid and the production of carbon dioxid. 



A series of sterilized cultures was compared with another series which had 

 been inoculated with earth rich in different micro-organisms and then incubated 

 at 30° C. for 15 days. It was found that under the conditions of the experi- 

 ments the biological processes played a negative rule, although the amount of 

 easily soluble phosphoric acid in the culture medium was materially lowered 

 even when an abundant formation of carbon dioxid indicated the activity of 

 the soil micro-organisms present. 



This decrease in easily soluble phosphoric acid was due to its consumption 

 by the bacteria and also to pure chemical reactions which finally transformed 

 the easily soluble phosphoric acid into a less soluble form. Tliis does not imply 



