COFFEE, TEA ETC. 179 



tomed to its use, particularly when taken at night, it produces persistent wake- 

 fulness. These effects are so well known that it is often taken for the pur- 

 pose of preventing sleep. 



Experimental researches have shown that the use of coffee permits a 

 reduction in the quantity of food, in workingmen especially, much below the 

 standard which would otherwise be necessary to maintain the organism in 

 proper condition. ' In the observations of De Gasparin upon the regimen of 

 the Belgian miners, it was found that the addition of a quantity of coffee to 

 the daily ration enabled them to perform their arduous labors on a diet which 

 was even below that found necessary in prisons where this article was not 

 used. Experiments have shown, also, that coffee diminishes the absolute quan- 

 tity of urea discharged by the kidneys. In this respect, as far as has been 

 ascertained, the action of coffee is like that of alcohol, and it may reasonably 

 be supposed to retard disassimilation, with the important difference that it is 

 followed by no unfavorable after-effects and can be used in moderation for 

 an indefinite time with advantage. 



A study of the composition of coffee shows a considerable proportion of 

 what must be considered as alimentary matter. The following is the result 

 of analyses by Payen : 



Cellulose 34-000 



Water (hygroscopic) 12-000 



Fatty substances 10 to 13-000 



Glucose, dextrine, indeterminate vegetable acid 15-500 



Legumine, caseine etc. 10-000 



Potassium chlorolignate and caffeine 3-5 to 5-000 



Nitrogenized organic matter 3-000 



Free caffeine 0-800 



Concrete, insoluble essential oil 0-001 - 



Aromatic essence, of agreeable odor, soluble in water 0-002 



Mineral substances ; potash, magnesia, lime, phosphoric, silicic, and sul- 

 phuric acid and chlorine 6'697 



100-000 



The above is the composition of raw coffee, but the berry is seldom used 

 in that form, being usually subjected to roasting before an infusion is made. 

 During this process, the grains are considerably swollen, but they lose sixteen 

 or seventeen per cent, in weight. A peculiar, aromatic substance is also 

 developed by roasting. If the torrefaction be pushed too far, much of the 

 agreeable flavor of coffee is lost, and an acrid, empyreumatic substance is 

 produced. 



Tea. An infusion of the dried and prepared leaves of the tea-plant is 

 perhaps as common a beverage as coffee, and taking into consideration its 

 large consumption in China and Japan, it is actually used by a greater 

 number of persons. Its effects upon the system are similar to those of coffee, 

 but they are generally not so marked. Ordinary tea, taken in moderate 

 quantity, like coffee, relieves fatigue and increases mental activity, but does 

 not usually produce such persistent wakefulness. 



