Physiologie. 543 



LiviNGSTON, B. E., J. C. Britton and F. R. Reid, Studies on 



the Properties of an Unproductive Soll. (U. S. 



Dept. of Agric. Bureau of Soils, Bulletin No. 28. Washington 



1905. p. 1—39.) 



A study of soil from Takoma Park Maryland. The 



soil in question is a brownish-yellow, coarse^ sandy loam, some 



three feet in depth, under vvhich is a clay. After a brief account 



of the physical and chemical nature of the soil, its physiologi- 



cal properties are discussed, the investigation of which forms 



the bulk of the subject of the paper. 



Certain plants grown in this soil show a decided stunting 

 of their organs. It is, hovvever, shown from experiments that 

 this condition is not due to lack of water in the soil. The 

 method of investigation was chiefly by means of transpiration 

 tests, carried on by weighing cultures made in parafin covered 

 baskets. Practically it was found that the soil can be improved 

 by the addition of fermented stable manure, green manure, 

 sumac and oak leaves, tannic acid, pyrogallol, calcium carbo- 

 nate, and ferric hydrate. In just what manner these substances 

 act cannot be determined, but it is apparent that the same 

 effects are produced whether the substance added be soluble 

 or practically insoluble. Hence it can hardly be that the bene- 

 ficial effect is caused by the increase of the nutrient content 

 of the soil, consequently the conclusion arrived at is that the 

 soil contains certain deleterious bodies and that the effect of 

 the insoluble substances is in some way to absorb these. It is 

 possible that some may act in a directly chemical manner, while 

 others may be purely physical in their action. The experi- 

 ments further indicate that in the case of wheat plants specifi- 

 cally deleterious substances are given off by the roots, a fact 

 which has bearing.on the matter of the rotation of crops and 

 also suggests that so-called „exhausted" soils, are_, in reality, 

 poisoned soils. Nothing definite can be said as yet as to the 

 nature of these toxic substances though they are probably 

 organic. H. M. Ricliards (New York). 



Martin, H. M., Studies on the Effect of some Con- 

 centrated Solutions on the Osmotic Activity 

 of Plants. (Bull. Torrey Bot. Club. Vol. XXXII. Aug. 1905. 

 p. 415—429.) 



Plasmolysis experiments with Potassium nitrate, Glycerin, 

 Urea, Acetamid, upon Pkilotria, Tradescantia, Beta, Spirogyra. 

 General results, action of plasmolysing Solution is to increase 

 the concentration of the sap. Glycerin and urea, the action of 

 which continues several hours, produce a relatively greater 

 increase than acetamid, which acts quickly. The increase in 

 concentration of sap is influenced by that of the plasmolytic 

 agent. The stronger the plasmolyzing Solution the greater the 

 increase. H. M. Richards (New York). 



