CONTENTS 11 



PROBLT5M PAGE 



XX. DIGESTION AND ABSORPTION .... 220 



184. To compare the digestive system of a frog with that of man . . 221 



185. To study my own teeth 222 



186. To demonstrate the function and structure of a simple gland . . 223 



187. To find the use of digestion 224 



188. To determine the conditions most favorable for gastric digestion . 224 



189. To determine another effect of gastric juice ..... 225 



190. To note the action of pancreatic juice on starch ..... 225 



191. To note the effect of pancreatic juice on oils and fats . . . 225 



192. To study the effect of artificial pancreatic juice on protein . . 226 



193. To find one action of bile 226 



194. To study the method and place of absorption in the human body . 227 



195. To understand the structure of a villus 227 



196. How may foods be absorbed by the villi ? 227 



197. To find the pathway of absorbed foods 228 



XXI. THE BLOOD AND ITS CIRCULATION . . . 232 



198. To prove that blood contains nutrients ...... 232 



199. To study the corpuscles of the blood 233 



200. To determine the effect of oxygen and carbon dioxide upon the blood 234 



201. To study the structure of the heart 235 



202. To study the circulation of the blood 236 



203. To determine the rate of your own heartbeat 237 



204. What is the effect of hard mental work on the pulse beat ? . 237 



205. What effect has exercise on the heartbeat ? 237 



206. How to stop the flow of blood in case of an accident .... 238 



XXII. RESPIRATION AND EXCRETION . . . 240 



207. To compare the structures of the lungs of the frog and of man . .241 



208. To determine changes that take place in air in the lungs . . .241 



209. To find the capacity of the lungs 242 



210. To study the mechanics of respiration 242 



211. To study the part the ribs play in respiration 243 



212. What is the function of the diaphragm ? 243 



213. To find out what becomes of the oxygen in the lungs . . . 244 



214. To make a study of ventilation ........ 244 



215. To study air for presence of dust (Home experiment) . . . 245 



216. To determine the best method of cleaning a room .... 245 



217. What makes a crowded, closed room uncomfortable ? 246 



218. To study the structure of the kidney 246 



219. The skin as an organ of excretion and heat control .... 247 



XXIII. BODY CONTROL AND HABIT FORMATION . . 251 



220. How are we aware of the world about us ? 251 



