LIBERATION OF ORGANIC MATTER By Roots oF GROWING Puants 43 
BIBLIOGRAPHY 
\meRIcCAN Pupiic HEALTH AssoctaATION. Report of committee on stand- 
ard methods of water analysis, p. 1-141. (Reference on p. 37.) 1908. 
Awpreé, G. Sur l’évolution de l’azote, du phosphore, et du soufre au 
cours de la végétation de l’orge. Acad. Sci. [Paris]. Compt. rend. 
154: 1627-1630. 1912. 
SROWTHER, CHARLES, AND Ruston, ArtHUR G. The influence of time of 
cutting upon the yield and composition of hay. Journ. agr. sci. 4:305- 
317. 1911-12. : 
ionEs, W. J., Jr., AND Huston, H. A. Composition of maize at various 
stages of its growth. Indiana (Purdue Univ.) Agr. Exp. Sta. Bul. 
175:595-630. 1914. 
kNupson, L. Viability of detached root-cap cells. Amer. journ. bot. 
6:309-310. 1919. 
——— The secretion of invertase by plant roots. Amer. journ. bot. 
7:371-379. 1920. 
4E CLERC, J. A., AND BREAZEALE, J. F. Plant food removed from growing 
plants by rain or dew. U. 8. Agr. Dept. Yearbook 1908:389-402. 
1909. 
tAMSAY, J. T., AND Ropertson, W. C. The composition of the potato 
plant at various stages of development. Victoria (Australia) Agr. 
Dept. Journ. 15 (1917) :641-655. 1918. : 
SCHREINER, OSWALD, AND Reep, Howarp S. The role of oxidation in 
soil fertility. U.S. Soils Bur. Bul. 56:1-52. 1909. 
SCHREINER, OSWALD, AND SuLLivaAn, M. X. Studies in soil oxidation. 
U.S. Soils Bur. Bul. 73:1-57. 1910. 
SCHULZE, B. Studien iiber die Entwickelung der Roggen- und Weizen- 
pflanze. Landw. Jahrb. 33:405-441. 1904. 
[READWELL, F. P. Reactions in the wet way. Jn Analytical chemistry. 
(Translated from the German by William T. Hall.) 4th English ed., 
feeo2. 1915. 
TRowpripcE, P. F., Haicu, L. D., anp Movutron, C. R. Studies 
of the timothy plant. Part II. The changes in the chemical compo- 
