258 ANNUAL OF SCIENTIFIC DISCOVERY. 



But instinct has taught them to make use of a substance, "which is capa- 

 ble of making a too scanty nourishment sufficient to the system, and by 

 by preventing in this way the otherwise unavoidable disturbances of the 

 balances of life. 



It is particularly coffee, tea, cocoa, empyreumatic oils and alcoholic 

 liquors, that possess this peculiar influence on the system, and most of 

 these agree in producing that excitement of the nervous system of so 

 great importance in social life. 



If we now reflect upon the distribution of these substances, we find 

 that one of them is used by the people as a common article of food, while 

 the others are enjoyed by the higher classes as articles of luxury. In 

 those countries where one or other of these substances is cultivated, its 

 culture is considered a matter of chief importance by the people : thus, in 

 Arabia, coffee ; in China, tea ; in the wJne-producing countries, wine. 

 On the contrary, where this is not the case, the choice has fallen almost 

 exclusively on coffee or tea. The reason why the preference is given to 

 these, particularly in Europe, is owing principally to the fact that they 

 exert a far less injurious influence upon the system than alcoholic drinks, 

 and also on account of their valuable action upon the nervous system 

 from the united effects of coffee and empyreumatic oil. For, while, by 

 stimulating the reason and imagination, these prepare man for intellectual 

 and bodily exertion, spirituous liquors, exciting only his imagination, 

 which degenerates by slight excess into confusion of thought, cause, by 

 irritating the nervous system, general debility. These latter, therefore, 

 can be used with much less safety than coffee or tea. 



An attentive consideration of the quality and quantity of the composi- 

 tion of coffee and tea, the various modes of preparing them, as well as 

 their action upon the system in connection with the kind of food used, 

 will probably account for the peculiar preferences of nations for the one 

 over the other. If the composition of tea leaves be compared with roasted 

 coffee, we find that they both possess those substances that are of such great 

 importance thein, ethereal oil, and protein substance. The only differ- 

 ence between them is, that the coffee contains an aromatic substance, and 

 the tea a greater amount of thein, but especially of ethereal oil. Three 

 most important effects are produced by these constituents: 1. The retard- 

 ing of metamorphosis produced by the thein, but more particularly by 

 the aromatic substance in coffee. 2. The lengthened activity of the brain, 

 produced by the special action of thein and ethereal oil. 3. Serving as an 

 actual means of nourishment, by the amount of protein substance con- 

 tained in them. Coffee influences more directly the metamorphosis, and 

 tea the nervous system. In order to obtain completely these effects of the 

 two drinks, they must be partaken of in substance. This occurs, how- 

 ever, only among few nations, and is probably dependent upon the kind 

 of food used and their mode of life. The Orientals and Arabs regard 

 coffee as a necessary article of food, and from their custom of drinking it 

 with the dregs, thus making the large amount of protein substance and 



