L28 abstracts: chemistry 



AGRICULTURAL CHEMISTRY.— The oxidative and catalytic poivers 

 of soils and subsoils. M. X. Sullivan and F. R. Reid. Science, 

 33: 339. 1911. 



Surface soils have the power to oxidize easily oxidizable substances 

 such as aloin, guaiac, pyrogallol, hydroquinone, etc. When ten grams 

 of soil are shaken with 500 cc. of a 0.1 per cent water solution of aloin, 

 the yellow color of the aloin is changed to cherry red. On allowing the 

 soil to settle, the solution can be filtered and the depth of color deter- 

 mined in the colorimeter. Broadly speaking, the oxidative power of 

 the soil is symptomatic of a good soil condition, since soils of good pro- 

 ductivity have in general good oxidizing power, while soils of poor pro- 

 ductivity have, as a rule, poor oxidizing power. Subsoils have little, 

 if any, action on aloin, though occasionally the oxidizing power of the 

 subsoil may be as great or greater than the corresponding surface soil. 

 The catalytic power of the soil or its capacity for decomposing hydrogen 

 peroxide with the liberation of free oxygen is roughly parallel to the oxi- 

 dative power, in that soils known to be of good productivity have strong 

 catalytic power, while poor soils have weak catalytic power. The oxi- 

 dative and catalytic powers of the soil are analogous to these powers 

 in plants and animals and are modified in much the same way. M. X. S. 



BIOLOGICAL CHEMISTRY. — Biological analogies in soil oxidation. 

 Oswald Schreiner and M. X. Sullivan. Proceedings of the 

 American Society of Biological Chemists, 2: 11. 1911. Journal 

 of Biological Chemistry, 9: XVII. 1911. 



The soil is the seat of many biochemical activities that directly or 

 indirectly affect fertility. Many of the processes in the soil are analo- 

 gous to those occurring in plants and animals. Soils may show fatigue 

 under a one-crop system and under unsanitary conditions may contain 

 material which is retardativeof plant growth. Many other compounds, 

 some of which are known to be products of proteolytic digestion, occur 

 in soils. The soil per se has oxidizing and catalyzing powers which in 

 cropped soils are due partly to activities of plant roots, but in air-dried 

 soils are due mainly to non-enzymotic soil constituents, inorganic and 

 organic, working separately, conjointly or in reinforcing and activating 

 combinations. The recently discovered activating action of salts or 

 organic hydroxyacids and the discovery that alfalfa laccase is a mixture 

 of salts of organic hydroxyacids have a close counterpart in soil oxida- 

 tion studies. O. S. and M. X. S. 



