650 PROCEEDINGS OF SECTION K. 



with quartz-sand, in which field-peas were grown. The sand in 

 both cases was supplied with the necessary mineral fertilizing con- 

 stituents, but with no nitrogen. Both plants grew vigorously, the 

 oats obtaining their supply of nitrogen by the diffusion of soluble 

 nitrogenous material from the outer pot in v/hich the legumes were 

 growing. 



If instead of a porous inner pot, the oats were grown in glazed 

 pots, and were thus unaffected by the nitrates formed by the 

 legumes, they produced a much diminished yield, and showed the 

 growth and colour associated with lack of nitrogen. 



Another case in which a beneficial action is exerted on the 

 growth of plants by organic soil-constituents, and one in which 

 such action cannot be attributed to any direct fertilizing power, is 

 furnished by creatinine and creatine. Creatinine is an organic 

 substance which exists not only in the humus of soils, but in farm- 

 yard and organic manures, and in many plants and seeds, and 

 whose presence in the soil has been found to indicate fertility. 



The United States Soil Bureau (Schreiner, Shorey, Sullivan, 

 and Skinner, Bull. 83, Bureau of Soils, U.S.A.) have isolated and 

 experimented with this substance, and with creatine, of which 

 latter it is the anhydride. These authors have found it in stable 

 manure and peas used as green manures; also in wheat seedlings, 

 wheat-grain, bran, rye, some leguminous plaiits, and potatoes. 



Both creatine and creatinine are nitrogenous substances, and 

 experiments in manuring show that they can replace nitrate in its 

 effects on plant-growth, at all events in culture solutions. 



Micro-Organisms — Toxic and Beneficial. 

 In yet another direction, a great deal of interesting work has 

 been done showing the part played by minute organisms in rela- 

 tion to soil fertility. It had been known for some time that treat- 

 ment of the soil both by heat and by antiseptics favoured the 

 growth of crops. 



S. U. Pickering {Journal Agricultural Science, Vol. 3, page 32, 

 and Vol. 3, page 258) found that when soils were either heated or 

 treated with antiseptics the total soluble organic matter of the soil 

 was increased, and at the same time toxic conditions were pro- 

 duced which hindered germination, such inhibitory action being 

 only temporary, as the toxins were subsequently destroyed, pre- 

 sumably by oxidation. 



E. J. Russell and H. B. Hutchinson {Journal Agricultural 

 Science, Vol. 3, p. Ill), in an elaborate and careful series of ex- 

 periments, appear to have shown conclusively that the beneficial 



