FOOD AND DRINK 105 



ing efforts of mind or body; it tranquillizes, but does not dis- 

 qualify for labor, and hence it is highly esteemed by persons 

 of literary pursuits. 



36. Another property of coffee is, that it diminishes the 

 waste of the tissues, and consequently permits the performance 

 of excessive labor upon an economical and inadequate diet. 

 This has been tested among the miners of Belgium. Their 

 allowance of solid food was below that found necessary in 

 prisons and elsewhere; but, with the addition of about four 

 pints of coffee daily, they were enabled to undergo severe 

 labor without reducing their muscular strength. The caravans 

 which traverse the deserts are supported by coffee during long 

 journeys and lengthened privation of food. Among armies it 

 is indispensable in supplementing their imperfect rations, and 

 in relieving the sense of fatigue after great exposure and long 

 marches. When taken with meals, coffee is also thought to 

 promote digestion. 



37. Tea. The effects of tea-drinking are very similar to 

 those of coffee, and are due to a peculiar principle called tlieine. 

 This principle is probably the same as that found in coffee 

 caffeine since the chemical composition of both is precisely 

 alike. Tea, as a beverage, is made from the dried leaves of 

 the plant by the addition of hot water ; if the tea be boiled, 

 the oil which gives it its agreeable flavor is driven off with the 

 steam. There are two kinds of tea the black and the green ; 

 the latter is sometimes injurious, producing wakefulness and 

 other nervous symptoms. The excessive use of either coffee 

 or tea will cause wakefulness. 



38. During Dr. Kane's expedition in the Arctic regions, the 

 effects of these articles were compared. " After repeated trials, 

 the men took most kindly to coffee in the morning, and tea in 

 the evening. The coffee seemed to continue its influence 

 throughout the day, and they seemed to grow hungry less 



36. Another property of coffee ? Miners of Belgium ? The Caravans ? Among armies ? 

 Taken with meals ? 



37. Effects of tea-drinking ? Peculiar principle ? The tea beverage, how made ? Black 

 and green tea ? Excessive use of tea or coffee ? 



38. Experiments made during Kane's expedition ? 



