xii CONTENTS 



CHAP. TAOE 



XI. MEMBRANES (PLASMAHAUT) 132 



Need for Cell Membrane, 132. Nature of, 133. Forma- 

 tion. 134. Composition, 135. Structure. 136. Per- 

 meability, 136-145. Electrical Osmosis, 140. Nega- 

 tive Osmosis, 140. Donnan Equilibrium, 143. Polari- 

 sation, 145. Selective Permeability, 145. 



XII. THE CELL 147 



Composition. 148. Nucleus, 149. Phenomena of Life : 

 (o) Movement. 150 ; (b) Irritability, (c) Ingestion and 

 Excretion, 151 ; (d) Growth, (e) Electric Phenomena. 

 152. Current of Action, 153. Artificial Cell, 153. 

 Polarisation Current, 154. 



XIII. RADIO-ACTIVITY 155 



Electrons, 156. Kathode, X. a, j8 and y Rays, 157. 

 lonisation, 158. Potassium, 159-162. JPhysiological 

 Effects, 163-164. Ultra-violet Rays, 164. Ergosterol, 

 165. 



SECTION III : CELL COMMUNITIES 



XIV. THE ARMY WHEREWITH THE BODY WAGES WAR 

 WITH NATURE—THE MUSCLE CELLS 166 



As Energy Transformers, 167. Structure, 168. Iso- 

 metric and Isotonic Contractions, 169. Muscular 

 Cycle, 171. Glycogen and Lactic Acid, 172. Lactic 

 Acid and Heat Evolved, 173. Function of Lactic Acid. 

 174. Theories of Muscle Action : (1) Surface Tension 

 Theory, 174. (2) Osmotic, (3) Imbibition. (4) Liquid 

 Crystal Theories, 176. (5) Condenser Theory. 177. 

 Temperature Coefficient, 177. Efficiency, 178. Elec- 

 trical Effects, 179. Rheoscopic Frog, 180. 



XV. MANUFACTURING CELLS 182 



Phases of Activity, 182. Conditions Controlling Secre- 

 tion, 183. Oxvgen Needs, 184. Mechanism of Secre- 

 tion, 185, 187^ Electrical Potential Developed. 186. 

 Heat Developed in Secretion, 187. 



XVI. THE ARMY FOR HOME DEFENCE .... 189 



Ciliated Cells, 189. Reticulo-Endothelial System. 190- 

 192. Formation of Gall-stones, 192. Kidneys, 193-202. 

 Structure, 193. Function of Bowman's Capsule, 194. 

 Saline Diuresis, 195. Gum Saline, 196. Sulphate 

 Diuresis. 196. Function of Tubules, 197. Work Done 

 by Kidney, 198. " Free " and " Bound " Water, 199. 

 Theories, 199-201. Other Glands of Elimination, 202. 



XVII. THE CIVIL ENGINEERS OF THE BODY . . . 203 



Epithelium. 203. Connective Tissues, 204. Stress and 

 Strain, 205. Hooke's Law, Young's Modulus, Shear 

 Modulus, 206. Bulk Modulus. Poisson's Ratio, Elas- 



