x CONTENTS 



acid 82. Toxic action of potassium hydrate 83. Substitution poisons 84. Toxic 

 action of phenol 85. Toxic action of phloroglucin 86. Toxic action of formalde- 

 hyde 87. Poisonous proteinaceous substances 88. Toxic action of alkaloids 

 89. Self-poisoning 90. Acclimatization to chemical action 91. Changes which 

 ensue in protoplasm during acclimatization 92. Chemotaxis 93. Relations of 

 the organism to trophic and other compounds 94. Chemotaxis of antherozoids of 

 ferns 95. Chemotactic movements of bacteria 96. Chemotropic movements of 

 pollen tubes 97. Chemotropic stimulation of stigmas for pollen tubes 98. Chemo- 

 tropism of Mucor, and other moulds to sugar 99. Influence of chemical stimulation 

 upon developmental processes. 



IV. RELATIONS OF PLANTS TO WATER 65-70. 



100. Water as a factor in living matter 101. Effect of desiccation upon move- 

 ment of protoplasm 102. Resistance of seeds to desiccation 103. Hydrotropic 

 reactions 104. Prohydrotropism of roots 105. Reactions of plasmodia to water : 

 hydrotropism 106. Rheotropic reactions of plasmodia 107. Influence of water 

 and water vapor on form 108. Form and structure of organs in water and watery 

 vapor. 



V. RELATION OF PLANTS TO GRAVITATION 71-88. 



109. Nature of the relation of gravitation to plants no. Nature of the stimu- 

 lating influence of the force of gravity in. Latent period, reaction time, presen- 

 tation period 112. Determination of reaction time 113. Determination of pre- 

 sentation time 114. Effect of slow revolution of clinostat 115. Influence of 

 external conditions upon geotropic reactions 116. Delayed reactions 117. After 

 effects of stimulation 118. Sensory zone of roots 119. Alternating and intermit- 

 tent stimulation 120. Rhythmic effects of alternating stimulation 121. Chemical 

 changes in a geotropically stimulated root 122. Transmission of geotropic impulses 



123. Mechanism of curvature of roots 124. Diageotropism of secondary roots 

 125. Sensory zone of shoots 126. Region and form of curvature 127. Mechanism 

 of curvature of grass stems 128. The geotropic relations of dorsiventral organs 

 129. Rotation and curvature of petioles of dorsiventral leaves in response to geotropic 

 stimuli 130. Geotropic curvatures in organs in which growth in length has ceased 



131. Diageotropism of flowers of Narcissus 132. Lateral geotropism of twining 

 plants 133. Revolving movements of tips of twining plants 134. Behavior of 

 twining plants when freed from the influence of gravity 135* Alterations in geo- 

 tropic properties 136. Recovery from a position assumed geotropjcally 137. 

 Recovery of position of roots 138. Formative influence of gravity. 



VI. DELATIONS OF PLANTS TO TEMPERATURE 8g-IOO. 



139. General relations of temperature to protoplasm 140. Tonicity to temper- 

 ature 141. Adjustment to changes in temperature 142. Stimulating influence 

 of changes in temperature 143. Resistance and acclimatization of seeds to heat 

 144. Relation of water content to endurance of high temperatures 145. Influence 

 of temperature upon movement of protoplasm 146. Relation of low temperatures to 

 resting seeds, bulbs and tubers 147. Freezing of unicellular organisms 148. 

 Freezing of tissues 149. General observations on freezing 15- Formative effect ; 

 thermal constants 151. Thermotropism 152. Thermotropism of leaves 153. 

 Thermotropic reactions of shoots 154. Influence of temperature upon the opening 

 or closing of flowers 155. Thermotropic reactions of tendrils, Dionaea, &c. 



VII. RELATION OF PLANTS TO ELECTRICITY AND OTHER FORMS OF ENERGY. 



101-109. 



156. Nature of influence of electricity upon plants 157. Measurement of differ- 

 ences in electric potential 158. Differences in potential due to metabolism r 159. 



