FOODS: THEIR CLASSIFICATION 439 



unlike the desire for food, increases as more is taken instead of 

 decreasing when satiety is reached. It thus requires a stronger 

 effort of will to leave off as more is taken, and since the alcohol 

 at the same time depresses the power of the will the danger of 

 Overindulgence is continually present. Only where the will is 

 sufficiently strong to set a limit and adhere rigidly to it is the con- 

 tinuous moderate use of alcohol in any degree safe. 



Returning to the question of the desirability of the practice of 

 removing the brakes from the brain periodically, it may be said 

 that the opinion seems to be becoming more and more prevalent 

 among neurologists that the use of alcohol for such a purpose, 

 particularly in early and middle life, is more of an injury than a 

 benefit. The normal interactions among the different parts of the 

 mental apparatus should be permitted, according to these ob- 

 servers, to proceed without artificial interference, at least during 

 the period of the most active associative processes. There seems 

 to be no vital objection to the moderate use of alcohol on the part 

 of persons who have passed the age of fifty or thereabouts. The 

 danger of acquiring the alcohol habit is practically nil at that age, 

 and the predominant mental traits are by that time so completely 

 in control that occasional release from them may operate as a 

 distinct advantage. This is particularly true in the case of those 

 dderly persons who find themselves disposed to a somewhat 

 gloomy outlook upon life. The temperate use of alcohol may 

 make life more enjoyable for themselves and also for those about 

 them. 



Tea, Coffee, and Cocoa. These beverages all owe their special 

 physiological properties to certain alkaloids present in them. 

 The active principle of tea and coffee is the same, caffein; that of 

 cocoa, and its derivative, chocolate, is a closely related substance 

 theobromin. Caffein and theobromin appear to be direct nerve- 

 stimulants. They cause a rise of blood-pressure through stimu- 

 lation of the vasoconstrictor center. Their use, like that of al- 

 cohol, constitutes an artificial interference with normal processes, 

 and is subject, therefore, to the general objections which arise 

 against such interference. Their effects are of varying intensity; 

 cocoa is an exceedingly mild stimulant; tea, properly made, is 

 somewhat stronger; and coffee, properly made, is stronger yet. 

 Their use is borne much better by some persons than by others. 



