INDEX 



215 



Poisonous substances in conducting 

 tracts after heating, 56 ff, 60 ff 



Poynting and Thomson, 115 



Pressure concentrates sap of tissues, 

 178 ff 

 for sap extraction, 175 

 Velocity of flow in stems, proportional 

 to, 135 ff 



Protoplasm, Semi-permeability of, 4, 

 179 ff 



Protoplasmic streaming and transmis- 

 sion of water in stems, 52, 53 



Protoxylem, Collapse of, 97 



Quincke's Theory, 83 



Secretion and transpiration, 7 ff 



of water, 8 ft' 



raising sap, 201, 210 

 Semipermeability of protoplasm, 4, 



179 

 Soap-film, cohesion of, 106 

 Stephan, 2 

 Stomata, area of, 1 



Diffusion through, 2, 3 

 Strasburger, 6, 26, 29, 46, 50, 80, 81, 



93, 94, 95, 100, 117, 138 

 Structure of wood and cohesion theory, 



91 ff, 210 



vital theory, 51, 210 

 Subdivision of conducting tracts, 91 ff, 



210 



RENNER, 194, 200 



Resistance and osmotic pressure, 195 

 of walls to flow, 42, 95 

 of water-tracts, 116 ff', 124 ff, 195 

 Effect of temperature on, 70 

 Ewart's estimates of, 116 ff 

 falsified by clogging, 125, 126 

 Respiration, Energy set free by, 202 

 necessary for transpiration under 

 water, 24 

 Root-Pressure, Function of, 95 

 Roots, Condensation of water on, 204 

 Osmotic pressures of, 45, 182, 184, 

 192, 193 



Sachs, von, 29, 46, 49, 83, 100 

 Sap-extraction, 175 ff 

 by centrifuge, 44, 57 

 chloroform, 176, 186 

 desiccation, 177 

 heat, 177, 186 

 liquid air, 181 ft' 

 pressure, 175 

 toluene, 180 

 Sap of conducting tracts changed by 

 heat, 55 ff 



concentration of, 39, 45, 58 

 contaminated by heat, 56 ft" 

 contamination of, removed, 



65 ff 

 extracted by centrifuge, 44, 57 

 oxydase in, 58 

 raised by evaporation, 203 



secretion, 7 ff, 210 

 sugars in, 59 



tensile strength of, 110 ff. 

 tissues, concentrated by pressure, 



178 ff 

 leaves, osmotic pressure of, 139, 

 190 ff 

 Schultz, 50, 80 

 Schwendener, 49, 80. 93, 198 



Tensile Film Theory, 83 

 strength of sap, 110 ff 



water, 103 ff 

 water, Bubbles in, 87, 89 

 rupture of, 86, 113 

 Tension in sap, measured by osmotic 

 pressure in leaf-cells, 141, 193 

 by flow, 194 



retards transpiration, 209 

 Tension theory, 87 ff 

 Thermo-couples, Calibration of, 169 

 Change in constant of, 171 

 Construction of, 157 

 Use in Cryoscopy of,- 156 ff 

 Thermo-electric method of cryoscopy, 



156 ff 

 Trachea?, Contents of, 91 ff' 



plugged by effects of heating, 54, 



60 

 Structure of, 96 ff 



without semi-permeable membrane, 

 4, 44 

 Transmission of water in walls, 

 29 ff 



through dead stems, 53 ff 

 stems as vapour, 42 



proportional to pressure, 135 

 Transpiring plant, model of, 204 

 Transpiration, a physical phenomenon, 

 6 

 and anaesthetics, 9 ff 



evaporation, compared, 1 

 secretion, 7 ff. 

 turgor, 6 

 controlled by supply, 122 

 -current, velocity of, 52, 132 

 Function of evaporation, osmosis and 



imbibition in, 3 ff 

 Function of living cells in, 7 ff, 201 

 influenced b} 7 solutes, 5 

 into saturated spaces, 17 ff 

 into various gases, 9 ff 

 under water, 23 



