FOODS. 155 



brings out the tannic acid that they contain, and produces 

 bad effects. 



Coffee. Coffee owes its stimulating effect to a sub- 

 stance called caff tin, which is considered identical with 

 thein. Coffee acts as a restorative after hard labor, seem- 

 ing to retard the wastes of the tissues and food. It is used 

 in the army (also in penitentiaries), not as a luxury, but as 

 a matter of economy in the matter of food supply. Coffee, 

 used to excess, frequently causes palpitation of the heart. 



Malted Milk. Malted and peptonized milk makes a 

 valuable drink for invalids and dyspeptics. 



Cocoa and Chocolate. Cocoa contains a stimulant 

 called theobromin. But unlike tea and coffee, cocoa and 

 the preparation from cocoa known as chocolate are true 

 foods by virtue of the fat contained. 



Beef Tea. Beef tea and various beef extracts are very 

 beneficial. There is not enough nourishment in them to 

 maintain strength without other food. Their nutritive 

 value has been somewhat overestimated. Their value is 

 probably much more in their stimulating than in their 

 nourishing effect. But many of the soups and drinks 

 made from these preparations are very beneficial. They 

 refresh the tired system wonderfully. If the man who 

 feels " fagged out" and takes a drink of liquor to " brace 

 him up," as he says, were to take a cup of hot bouillon, he 

 would find himself braced up for the time, without any bad 

 reaction, or permanent injury to the system, which follow 

 the use of alcohol. 



Cooking. Cooking is designed to make food more 

 palatable and more digestible. Some foods, such as eggs, 



