288 
F. C. Newcombe 
REFERENCES 
(1) Blackman, V. H. Theory of Geotropic Response. New Phytologist, 20, 
p. 38. 1921. 
(2) Coupin. Sur une tige a geotropisme horizontal. Compt. rend. Acad. 
Sciences, Paris, 172 , p. 608. 1921. 
(3) Lynn, M. J. The Reversal of Geotropic Response in the Stem. The Effect 
of Various Percentages of Carbon Dioxide. New Phytologist, 20 , p. 116. 
1921. 
(4) Small, James. A Theory of Geotropism with some Experiments on the 
Chemical Reversal of Geotropic Response in Stem and Root. New 
Phytologist, 19 , p. 49. 1920. 
(5) Small, James and Lynn, M. J. II. On the Angle of Balance of Roots, 
Stems, and Leaves. New Phytologist, 19 , p. 209. 1920. 
(6) Small, James and Rea, M. W. Preliminary Notes on Additional Evidence 
for the Hydrion Differentiation Theory of Geotropism. I. On the 
Reversal of Geotropic Curvature in the Stem. New Phytologist, 19 , 
p. 208. 1920. • 
(7) Snow, R. The Hydrion Theory of Geotropism. New Phytologist, 20, p. 247. 
1921. 
CAMBRIDGE: PRINTED BY W. LEWIS AT THE UNIVERSITY PRESS 
