SCIENCE 



Friday, November 1, 1912 



CONTENTS 

 The American Association for the Advance- 

 ment of Science: — 

 Some Chemical delations of Plant and Soil : 



PROPESSOK W. J. V. OSTERHODT 571 



The Organic Constituents of Soils: Oswald 

 SCHKEINEK 577 



The Drift in Secondary Education: Dk. Wil- 



LARD J. FiSHEE 587 



Scientific Notes and News 590 



University and Educational News 593 



Discussion and Correspondence: — 



An Electromotive Force due to Mechanical 

 Acceleration: Peopessoe D. E. Comstock. 

 Beversion of Amilystoma: R. D. O. John- 

 son. The Life Histories of the Fern Eusts 

 of the Genus Uredinopsis: W. P. Feasee. 

 "Pawlow" : Peofessor J. F. Abbott. 594 



Scientific Books: — 



Bonola's Non-Euclidean Geometry: Pro- 

 fessor Geoege Beuce Halsted: Allen's 

 Commercial Organic Analysis: Peopessoe 

 W. A. Notes. Eeadley's The Flight of 

 Birds: F. A. L 595 



Special Articles: — 



The Evening Primroses of Dixie Landing, 

 Alabama: Peopessoe Hugo de Veies and 

 H. H. Bartlett. The Great Crested Grebe 

 and the Idea of Secondary Sexual Charac- 

 ters: J. S. HuxLET. Volcanic Action in 

 the Black Sills of South Dakota: N. H. 

 Dabton 599 



The International Congress of Prehistoric 

 Anthropology and Archeology: Pbopessoe 

 Geoege Geant MacCdedy 603 



MSS. intended for publication and books, etc., intended for 

 review should be sent to the Editor of Bcibnce, Garrison-on- 

 Hudson, N^. Y. 



TEE AMEBIC AN ASSOCIATION FOB THE 



ADVANCEMENT OF SCIENCE 



SOME CHEMICAL BELATIONS OF PLANT 



AND SOIL'- 



In order to arrive at a satisfactory the- 

 ory of living matter it is evidently neces- 

 sary to know what substances are indis- 

 pensable to metabolism and to ascertain 

 the role of each of these substances. 



Despite much study it is not yet clear 

 what constituents of the soil are absolutely 

 needful for plants. An excellent example 

 is found in sodium chloride, which is in- 

 dispensable for animals, but is generally 

 thought to be unnecessary for plants. 

 This difference between plants and animals 

 would be of fundamental importance if 

 true in all cases, but recent experiments 

 have shown that sodium chloride is just as 

 necessary for many marine plants as it is 

 for animals. It would not be surprising 

 to find cases where sodium or chlorine are 

 likewise necessary for land plants. 



The condition in which the necessary 

 substances exist in the soil has both prac- 

 tical and theoretical importance. In cer- 

 tain forms they are said to be "available" 

 to the plant, in others not. A convenient 

 method of determining quantitatively the 

 substances which are "available" in a soil 

 is one of the prime needs of practical soil 

 study. In view of the difficulties with 

 existing methods it would seem worth while 

 to try to separate the available salts from 

 the soil by means of an electric current. 



' An address delivered at the Symposium on the 

 Soil before Section G, American Association for 

 the Advancement of Science, at Washington, 1911, 

 the scope being limited to a brief presentation of 

 elementary principles. 



