12 CONTENTS 



221. To determine what parts of the body are most sensitive to () touch, 



(6) heat and cold 252 



222. To study the anatomy of the nervous system 253 



223. To study the structure and use of neurons ...... 254 



224. What is a reflex action ?......... 254 



225. To compare the reaction time of hearing and touch .... 254 



226. To compare a reflex action with an act of thought .... 255 



227. To study habit forming 255 



228. To study the mechanism of habit formation 256 



229. To consider some harmful habits ....... 257 



230. How to go to work to form good habits . . . . . . - 257 



231. To determine the relation between taste and smell with reference to 



food flavors "... 258 



232. How to find out certain defects of vision in the laboratory . . 259 



233. What are some of the effects of alcohol on the nervous system ? . 259 



XXIV. MAN'S IMPROVEMENT OF HIS ENVIRONMENT . . 262 



234. How to ventilate my bedroom (Home problem) 263 



235. To compare the duster and the dry cloth with the moist cloth in 



cleaning the schoolroom ........ 2(53 



236. What should I eat for luncheon ? 204 



237. To make a sanitary map of my own environment .... 265 



238. To determine the bacterial content of different grades of milk . . 266 



239. To determine the bacterial content of some kinds of water . . 267 



240. To determine some of the problems of water supply and sewage dis- 



posal for a city 268 



241. Is typhoid a city or a country disease ?...... 269 



242. What is the annual cost to New York city of some preventable 



diseases? 269 



243. What are the chief causes of death in a city ? . . . . 272 



244. To study the relation of the death rate to the season .... 272 



245. To find a relation between flies and mortality ..... 272 



246. To determine the number of school children who needed treatment 



for different diseases in New York city, 1914-1915 . . .273 



247. How to discover the presence of adenoids 274 



248. To find some ways of preventing the spread of disease . . . 274 



249. First aid in the home. A summary of what to do and how to do it . 277 



