Index of Authors vii 
PAGE 
Salisbury, E. J. The Study of Human Implements as an Aid to 
the Appreciation of Principles of Evolution and Classifi¬ 
cation . . . . . . • 1 79 
Saxton, W. T., see Dastur 
Small, James. The Hydrion Differentiation Theory of Geo- 
tropism: a reply to some criticisms . . . . 73 
- Notes on an Easy Method of Camera Lucida drawing 
(2 Text-figs.) ...... 238 
Snow, R. The Hydrion Theory of Geotropism . . . 247 
Stiles, Walter. Permeability 
I. Introduction . . . . . *45 
II. The System Involved . . . . .48 
III. Surface Phenomena (2 Text-figs.) . . -93 
IV. Diffusion . . . . . • I 37 
V. The Permeability of Membranes (1 Text-fig.) . 185 
T(ansley), A. G. Some Recent Text-Books [Review]. 1. An 
Introduction to the Structure and Reproduction of Plants 
(Fritsch and Salisbury). 2. Text-Book of Plant Biology 
(W. Neilson Jones and M. C. Rayner). 3. Text-Book of 
Botany for Medical Students (J. Small) . . .132 
-Genetics and Evolution (Hagedoorn, A. L. and Hage- 
doorn, A. C.) [Review] . . . . .124 
W(adham), S. M. Germination in its Electrical Aspect (Baines, 
A. E.) [Review] . . . . . *136 
