174 MUCILAGE WATER. 



from very many plants, and is an important article in medicine and in 

 the arts. Of the gums thus used we shall speak particularly in the 

 next volume. The grains contain from 1 to 18 per cent, of mucilage, 

 the largest proportion being in wheat flour. Rye meal also contains 

 11 parts in the 100; the kidney bean 19.37, and marsh-mallow root 

 35.64. The properties of the gummy matters in different plants differ 

 materially. Gums likewise differ much in their composition and solu- 

 bility. Their chief constituents are carbon and water. They have 

 Been thought to possess nutritive principles, but are now considered an 

 element of respiration, as before asserted. - They are of difficult di- 

 gestion, and therefore not apt to agree with dispeptics ; still they are 

 employed by invalids as a demulcent and in some inflammatory dis- 

 eases. In coughs, irritations of the throat, &c. they are used in va- 

 rious forms, as we shall hereafter show. 



Water. It has been stated throughout this work that water is a 

 paramount and an essential constituent of plants, and consequently of 

 vegetable food. It is equally essential in all the vital functions of 

 animals ; hence it was anciently thought the primary principle of vi- 

 tality. It is seen to compose a large portion of the organs of human 

 and animal bodies, as well as of all plants, with the exception of some 

 few infusoria and mosses. Flesh contains about 74, and the blood 80 

 per cent, of water; thus it is estimated to constitute about three- 

 rths, by weight, of the human system. This being rapidly con- 

 sumed by the secretions, it follows that both animals and plants must 

 be often and abundantly supplied with it. In this respect it is more 

 essential to animal life than solid food, and is intermediate between 

 that and air. 



Some, however, have considered it unimportant as a drink, and 



j Ay*k have abstained from its use ; but they have, nevertheless, consumed it 

 in nearly equal quantities in succulent vegetable food. As this is com- 



r F/M&rw* posed of nearly 5-6ths of water, and as the quantity of water drunk by 

 an adult in health is about 6 pounds in 24 hours, it is probable that a 

 free use of succulent vegetables affords nearly, if not quite, as much 

 water as that usually drunk by an individual. It is not so important as 

 to how this fluid is taken ; but that it is essential to health and the 

 functions of the body, no rational person will deny, when it is con- 

 sidered that about 40 oz. are given off from the skin and lungs in 24 

 hours, in addition to that passed otherwise. 



Entering into the composition of most solid food, it is taken into the 

 stomach in that state and in drinks. It is in the form of a hydrate in 

 many substances, as in starch, sugar, albumen, &c., or when these 

 are in a moist state. It exists in the grains in the proportion of 14 to 

 20 per cent., legumes 14 to 16, potatoes 75, turnips 92, carrots 87, 

 beet root 87, and most other edible roots in like proportions ; cabbage 

 92. 



