SOILS — FERTILIZERS. 815 



of some of these compounds has been studied with wheat seedlings. Mineral 

 nutrient solutions with phosphate, potash, and nitrate in varying proportions 

 were used, and to these were added 50 parts per million of the compound tested. 



" The neutralized nucleic acid as well as its nitrogenous decomposition prod- 

 ucts, hypoxanthin and xanthin, had a beneficial action on the plants, promoting 

 growth and decreasing the nitrate absorption. The plants appear to be able to 

 utilize these compounds directly in their metabolism and require under these 

 circumstances less nitrate for maximum growth." 



Orig'in of creatinin in soils, M. X.. Sullivan (Ahs. in Science, n. ser., S5 

 (1912), No. S97, p. 390). — This is an abstract of a paper presented at the Wash- 

 ington meeting of the American Chemical Society in 1911 and containing results 

 previously noted (E. S. R., 26, p. 419). 



Studies on soils subjected to dry heat, E. D. Clark and F. J. Seaver (A6s. 

 in Science, n. ser., 3-5 (1912). No. 897, p. 389). — The paper presented at the Wash- 

 ington meeting of the American Chemical Society in 1911, of which this is an 

 abstract, reports an extension to green plants of earlier observations by the 

 authors on the effect of heating soils on the growth of fungi. 



It was found that " different degrees of dry heat give soils whose aqueous ex- 

 tracts have a brown color the depth of which is proportional to the intensity of the 

 heat. The amount of soluble matter, organic, inorganic, nitrogen, etc., was also 

 proportional to the different temperatures (90 to 180° C). The dark extracts 

 from strongly heated soils were favorable for fungus growth but were distinctly 

 unfavorable to lupine seedlings grown in them, this inhibiting action being 

 greatest in the darkest-colored extracts. Oats sown in a series of soils heated 

 to different temperatures showed a slight stimulation for the temperature up 

 to 125°, when compared with the unheated soil as a control, while above 125° 

 the heated soil had a very toxic effect. The organic matter of the darker 

 extracts gives nearly all the tests for reducing sugars, is largely precipitated 

 by acetone, smells like caramelized sugar, and has a strong acid reaction to 

 litmus." 



Partial sterilization of g'lasshouse soils, E. J. Russell (Gard. Chron., 3. 

 ser., .51 (1912), Nos. 1312, pp. 97, 98, figs. 3; 1313, pp. 113, 111,, fig. 1).—A brief 

 account is here given of the application of the results of the author's inves- 

 tigations on partial sterilization of soils (E. S. R., 22, p. 121) to the sick soils 

 thrown out from commercial cucumber and tomato greenhouses. The results 

 led to the conclusion that by partial sterilization, preferably by heating to 

 about 200° F., growers of tomatoes and cucumbers under glass may at small 

 cost be saved from what has hitherto been the expensive necessity of frequently 

 renewing their soils. 



Partial sterilization of soil for glasshouse work, E. J. Russell and F. R 

 Petherbeidge (Jour. Bd. Agr. [London], 18 (1912), No. 10, pp. 809-826, pis. //).— 

 This is a more detailed account of the investigations briefly referred to above, 

 and includes studies with chrysanthemums, spinach, radishes, tomatoes, cucum- 

 bers, and various ornamental plants. The conclusions reached are summarized 

 as follows : 



" Partial sterilization of soil increases the supply of food for the plant, some- 

 what alters the growth of the plant, and kills insect pests. 



" It may cause a temporary retardation in germination and in early growth, 

 the amount of which varies according to the nature of the soil, the seed, and 

 the general conditions. 



" In our experiments it has not proved advantageous for pot work where 

 abundant supplies of clean virgin soil and manure are available. 



" It is, however, very useful for work with borders, cold frames, and for 

 plants that are to run for some time without manure. It leads to better root 



