t!ONt>IMENTS, TEA, COFFEE* 473 



5. The Green Vegetables are specially rich in salts, which resemble the 

 salts of the blood; thus, dry salad contains 23 per cent, of salts, 

 which closely resemble the salts of the blood. Of much less importance 

 are the starch, cell-substance, dextrin, sugar and the small amount of 

 albumin which they contain. 



235. Condiments Coffee Tea Chocolate- 

 Alcoholic Drinks, 



Some substances are used along with food, not so much on account of their 

 nutritive properties as on account of their stimulating effects and agreeable 

 qualities, which are exerted partly upon the organ of taste, and partly upon the 

 nervous system. These are called condiments. 



Coffee, tea, and chocolate are prepared as infusions of these substances. Their 

 chief active ingredients are respectively caffein, them (C 8 H 10 N 4 2 + H 2 0), and 

 theobromin (C7H8N40 2 ), which are regarded as alkaloids of the vegetable 

 bases, and which have recently been prepared artificially from xanthin (E. Fischer). 



These "alkaloids" occur as such in the plants containing them; they behave 

 like ammonia ; they have an alkaline reaction, and form crystalline salts with 

 acids. All these vegetable bases act upon the nervous system ; some more feebly 

 (as the above), others more powerfully (quinine); some stimulate powerfully, or 

 completely paralyse (morphia, atropin, strychnin, curarin, nicotin, muscarin). 



All these substances act on the nervous system; they quicken 

 thought, accelerate movement, and stir one to greater activity. In 

 these respects they resemble the stimulating extractives kreatin and 

 kreatinin of beef-tea. Coffee contains about J per cent of caffein, 

 part of which is only liberated by the act of roasting. Tea has 6 per 

 cent, of thein, whilst green tea contains 1 per cent, ethereal oil, and 

 black tea J per cent.; in green tea there is 18 per cent., in black 15 

 per cent, tannin; green tea yields about 46 per cent., and the black 

 scarcely 30 per cent, of extract. 



The inorganic salts present are also of importance; tea contains 3*03 

 per cent, of salts, and amongst these are soluble compounds of iron, 

 manganese, and soda salts. In coffee, which yields 3 '41 per cent, of 

 ash, potash salts are most abundant; in all three substances the other 

 salts which occur in the blood are also present. 



Alcoholic Drinks owe their action chiefly to the alcohol which they 

 contain. The alcohol, when taken into the body, undergoes certain 

 changes and produces certain effects : 1. It is oxidised chiefly into 

 C0 2 and H 2 0, so that it is so far a source of heat. As it undergoes 

 this change very readily, when taken to a certain extent it may act as 

 a substitute for the consumption of the tissues of the body, especially 

 when the amount of food is insufficient. Small dosea diminish the 



