FOODS: THEIR CLASSIFICATION 395 



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 elderly 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 

 alcohol, constitutes an artificial interference with normal proc- 

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

 arise against such interference. Their effects are of varying in- 

 tensity; 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. They are not dangerous in the sense that alcohol is, 

 through an increasing craving which readily leads to overindul- 

 gence and resulting disaster, although they, like alcohol, are often 

 taken to excess. Temperance in the use of these beverages is as 



