64 STUDIES IN PHYSIOLOGY 



tends to injure the lining of the stomach. For these reasons, 

 too, the tea " grounds " should never be used a second time 

 for the preparation of tea. The finest and most delicate por- 

 tion of a tea infusion is that which is poured off within three 

 or four minutes, for this will be found to have the best 

 flavor and the least of tannin and other harmful compounds. 



" When properly made, tea in moderation is a wholesome, 

 agreeable, and refreshing stimulant beverage, particularly 

 grateful in conditions of mental or physical weariness. 

 Used in excess, it exerts a harmful influence upon the ner- 

 vous system, arid in a too strong form injures the digestive 

 organs." The foregoing remarks, quoted from Harrington's 

 "Practical Hygiene," apply to adults rather than to growing 

 children and youths; for in early life stimulants of every 

 kind should be avoided as much as possible, as they tend to 

 interfere with the healthful development of protoplasm. 

 We should remember that tea is in no sense a food, and so 

 cannot be of use in repair or growth of tissue; both of which 

 functions are of prime importance during the first twenty 

 years of life. 



Use and Abuse of Coffee. Most that has been said in 

 regard to tea applies equally well to coffee, except that in 

 its preparation the infusion should be put on the stove and 

 allowed to come to a boil; it should then be put on the back 

 of the stove until used. "Coffee acts as a decided stimulant 

 to the nervous system ; it doubtless enables adults better to 

 perform hard work, and diminishes for them the sense of 

 weariness; " but in the diet of a growing child, both tea and 

 coffee should be used very sparingly, if at all, since they 

 simply excite the organs to unnecessary activity. 



3. TOBACCO 



Effect of Tobacco on Growth. In discussing the effects of 

 tobacco, it is important, as was the case with tea and coffee, 

 to distinguish between the results of its use by the young 



