212 PHYSIOLOGY. 



their preparation undergo fermentation, producing alcohol, 

 though not ordinarily in large amounts. By giving such 

 drinks (often called "temperance drinks") to children, an 

 appetite for alcohol may be cultivated and the beginning 

 of a terrible habit made. (And it may be well here to note 

 the real meaning of the word habit, tJiat which holds us.) 



Cider. Nor is it "advisable to keep cider about a house 

 where there are children. " It is perfectly sweet," you 

 say. Yes, but unless it is all soon consumed it will fer- 

 ment. It is unwise, to say the least, to put temptation 

 in the way of those whose habits are not formed. 



STIMULANTS. 



[WILLIAM H. HOWELL, Ph.D., M.D., Professor of Physiology, Johns Hopkins University, 

 American Text-Book of Physiology.} 



" The well-known stimulating effect of alcohol, tea, 

 coffee, etc., is probably due to a specific action on the 

 nervous system whereby the irritability of the tissue is 

 increased. The physiological effect of tea, coffee, and 

 chocolate is due to the alkaloid caffeine (trimethyl xanthin) 

 and theobromine (dimethyl xanthin). In small doses these 

 substances are oxidized in the body and yield a correspond- 

 ing amount of energy, but their value from this standpoint 

 is altogether unimportant compared with their action as 

 stimulants. Alcohol also, when not taken in too large 

 quantities, may be oxidized in the body, and furnish a not 

 inconsiderable amount of energy. It is, however, a matter 

 of controversy at present whether alcohol in small doses 

 can be considered a true foodstuff, capable of serving as a 

 direct source of energy, and of replacing a corresponding 

 amount of fats or of carbohydrates in the daily diet. The 

 evidence is partly for and partly against such a use of al- 



