296 



SCIENCE 



[N. S. Vol. XXVII. No. 686 



organic bodies in soils demands methods 

 for their detection, isolation and study. 

 Their presence and toxic properties are de- 

 termined by physiological methods in 

 which plants are employed. The isolation 

 and identification must be done by chemical 

 methods, employing the methods of toxi- 

 cology and of biological and organic chem- 

 istry. The authors outlined methods of 

 separating the organic matter from the 

 large mass of inorganic material, and 

 further separation of the pure organic 

 body from the extraneous organic matter 

 by methods of extraction, solution, pre- 

 cipitation, distillation, etc. The specific 

 methods by which several harmful organic 

 compounds have already been isolated from 

 unproductive soils were given to illustrate 

 the general principles involved. 



Nitrates as Soil Renovators: Oswald 

 ScHKEiNEB and HowAED S. Eeed. 

 Attention is called in this paper to an 

 action of nitrates in aiding the destruction 

 of harmful organic bodies which may be 

 present in unproductive soils. After 

 nitrates have acted in such a soil or- soil 

 extract, the conditions for plant growth 

 are improved, although the nitrates have 

 been used up by a previous crop. Roots of 

 plants possess a strong oxidizing power 

 and it has been found that this power is 

 greatly augmented by nitrates, so that the 

 oxidizing power under such conditions be- 

 comes sufficiently great to destroy harmful 

 organic bodies, resulting in improved con- 

 ditions' for plant growth. When known 

 toxic bodies are used in the experiments, 

 their destruction by the plant and nitrates 

 can be showa by chemical analysis. 



The Proteicls of Cotton: H. C. White. 



This paper presents the results of the 

 first of a proposed series of observations 

 upon the nitrogen feeding of the cotton 

 plant. During the season of 1907 analyses 

 were made of pot-grown and field-gTown 



plants, from sprouting to maturity, to de- 

 termine the extent and character of the 

 nitrogen compounds. The actual nitrogen 

 content, at comparatively short intervals of 

 growth, is shown and some valuable siig- 

 gestions gained on which to base future 

 studies of the development of the nitrogen 

 compounds. The investigation will be 

 continued through the coming season. 



The Volatilization of Certain Mineral Ele- 

 ments in Ashing Plant Materials: W. W. 

 Skinner, U. S. Department of Agricul- 

 ture. 



The usual method for determining the 

 mineral matter in plants has been to ash 

 the material and submit the ash to a com- 

 plete mineral analysis; this presupposes 

 that all of the mineral elements in the 

 plant are retained in the ash, an assump- 

 tion which for a long time has been known 

 to be incorrect. 



This work was undertaken to show to 

 what extent sulphur, phosphorus, chlorin 

 and potash are lost by the ordinary method 

 of incinerating in air, and to point out the 

 possibility of faulty conclusions resulting 

 from the attempt to establish the relation 

 of plant growth to the mineral elements 

 in the soil from ash analyses which do 

 not show all of a certain mineral element 

 in the plant, a portion of it being vola- 

 tilized in the process of ashing. 



This paper gives results upon sulphur 

 only, and shows the loss when ashed by the 

 ordinary method as compared with the 

 total sulphur obtained by the peroxide and 

 the combustion in oxygen methods. 



Analyses are given of two samples of 

 cotton seed meal, two samples of mustard 

 seed meal, three samples of malt, four 

 samples of barley and three samples of 

 wheat. The loss of sulphur varies from 

 89 per cent, to 97 per cent. 



The Occurrence of Copper in Oysters: J, 



T. WiLLAED. 



