LIQUID FOOD. ] 



CHEMISTRY. 



349 



proportion, moderates the sourness, which in the unripe 

 fruit predominates over the sweet, though the quantity 

 of acid is actually smaller. 



In ripe fruit the acid is enveloped in the sugar, just 

 as in stewed fruit it is by the jelly ; for the vegetable 

 jelly of the raw fruit deserves this name only when 

 stewed. It is true, by this process, a new acid, the gela- 

 tinous or pectic acid, is formed. The latter, however, 

 in the form of a mucous jelly, weakens the other acids. 

 Stewed fruits and fruit-jelly, prepared with sugar, are 

 therefore less injurious than raw fruits, so far as con- 

 cerns the irritating power of the acids and salts ; for the 

 interior coating of the digestive tube is protected by the 

 gelatinous acid. 



Apples and berries, cherries and plums, apricots and 

 peaches, melons and cucumbers, with all other similar 

 fruits, dissolve the albuminous matters, and exercise a 

 cooling influence upon the blood. While more nutritious 

 than vegetables, and less so than potatoes, they have a 

 great advantage over the latter in not over-loading the 

 blood with fat. A thinner blood circulates with much 

 vivacity through the vessels of the inhabitants of the 

 South Seas ; "these blessed countries," to use the words 

 of Forster ; ' ' the cradle of the younger human race, where. 

 not yet condemned to slavery, it enjoyed all the rights 

 of free men, without being compelled to purchase at too 

 !ii--h a price the happiness of existence in sweat and 

 exhaustion." 



> >.v LIQUID FOOD. 65. Water. If life consist in a 

 unorphosis of the tissue, fluids are an indispensable 

 condition of life'; for the combinations and decom- 

 positions in its substance, produced by the activities 

 of our body, cannot take place without the agency of 

 water. The simplest beverage is therefore, at the same 

 time, the most necessary of all. 



It is true, the same combination of hydrogen with 

 oxygon, which constitutes the essential ingredient of all 

 drinkable water, is contained in a small proportion even 

 in the driest food ; but neither meat nor bread, still less 

 the leguminous seeds, are so abundant in water as to be 

 capable of maintaining the proper composition of the 

 blood. And who is not aware, from his own experience, 

 that the most nutritious aliments are precisely those 

 which most stimulate our thirst ? 



But it is impossible, in our climate, with our activity, 

 with the vigour of our changing tissues, to live only on 

 fruit and vegetables, meat and bread, and peas and 

 beans. Our most important aliments must be inter- 

 mingled with a food abounding in water, if the water, 

 which Ls abstracted from the body through the skin and 

 lungs, the intestines and kidneys, is to be restored by a 

 process of uninterrupted attraction. 



Our drinking-water is a nutriment which contains the 

 greatest proportion of liquid ; for is that not a nutri- 

 ment which conveys to the blood the substance that 

 renders possible the motion of all other combinations 1 

 Is not the water to be considered a restorative sub- 

 stance, inasmuch as the water, which constitutes three- 

 fourths of the blood, is continually being withdrawn by 

 all excretive organs, without exception ? 



And yet drinking-water is nutritious not alone because 

 it contains water. The warmfh of the earth indefati- 

 gably raises water into the air. From brooks, rivers, 

 and seas, from plants also, and animals, there arise unin- 

 terruptedly, through the action of heat, vapours, which 

 are condensed into clouds in the higher strata of the 

 atmosphere. If that were true, which in a coward 

 passion for repose has so often been imputed to nature, 

 that its activity never deviates from the strictest method 

 of quiet development ; evaporating water, if falling 

 down as rain, would provide us with water only. But 

 the dashing of the sea, and the storms of the air sur- 

 rounding the earth, the pressure of the atmosphere, and 

 the power of fire, very often impel the vapour upwards 

 witli so furious a violence, that all substances digs 

 in the water are carried with it. Hence, even the purest 

 water falling down from the clouds, is impregnated with 

 alts. Common salt and chloride of potassium, lime and 

 magnesia combined with sulphuric and carbonic acids, 



magnesium with chlorine, even iron and manganese, have 

 been found in rain-water ; and however slight the pro- 

 portionate amount of these fire-proof constituents may 

 be, the regularity of their indications establishes the 

 law. 



In a greater abundance, however, than with these 

 solid bodies, rain-water is impregnated with air. Oxygen 

 and nitrogen, and the most important nutriments of the 

 plants, carbonic acid and ammonia, are taken up by 

 the falling rain watering the thirsty earth, and fertilising 

 the fields ; and even the lightning renders its assistance 

 in enriching the verdant clothing of the ground. Its 

 spark unites nitrogen and oxygen into nitric acid, and 

 the thunder-shower supplies to the plant the nitrate of 

 ammonia. 



To ammonia especially, rain-water owes its softness ; 

 while lime renders the water, containing a greater pro- 

 portion of salts, hard, as we have it in our wells and 

 springs. The carbonic acid of the water dissolves the 

 chalk of the earth, and the water itself dissolves the 

 gypsum, or sulphate of lime, which forms the deposit 

 when, in the process of boiling, a considerable quantity 

 of water is evaporated. This is well known as occurring 

 in kettles, boilers, &c. 



The quality of spring-water is as various as the earth 

 through wliich it oozes. Earths and alkalies, combined 

 with chlorine or sulphuric acid, with carbonic or nitric 

 acid, with iron and manganese, are contained in the water 

 of wells and springs in the most varying proportions. 

 One or the other of these substances is often absent. 

 Phosphoric acid rarely, if ever, forms a constituent of 

 water, notwithstanding the predominance of the lime- 

 salts in wells and fountains. 



That which causes the water of swamps and lakes, of 

 rivers and seas, to be almost always untit for drinking, 

 is the admixture of putrefying organic substances, be- 

 sides the common salt of the sea, which impart a putrid 

 taste to it. Now it is the bottom of the sea, which, likfe 

 a retort, sends the water up into the air ; from wliich, 

 as if distilled into rain, it streams down again in a pota- 

 ble condition : now it is the earth, forming, as it were, 

 a strainer, through which the water, though not entirely 

 purified, bubbles out of the wells. Even the skin of 

 man possesses some of the properties of a filter. Cast 

 upon a rock where not a drop of fresh water refreshes 

 the languishing tongue, the shipwrecked man bathes in 

 the sea in order to escape the most tormenting death 

 from thirst ; and from the sea-water itself, a refreshing 

 moisture, with a smaller proportion of salt, penetrates 

 the thirsty body. 



CO. Water Essential to Digestion. Since the last re- 

 sult of the whole process of digestion is a liquefaction of 

 the alimentary principles, the formation of blood is im- 

 possible without water ; but not only the formation, but 

 the continual exorcise also of the organs, depends upon 

 their receiving a due amount of water. Without it, no 

 digestion or formation of blood, no nutrition or excretion 

 can exist. Even this statement, however, by no means 

 exhausts the importance of water ; for it is essential, not 

 only as the medium for the movement of all dissolved 

 substances, not only as the humidity necessary for the 

 organs, of which the most active, the brain and the 

 muscles, contain the greatest proportion of water ; but 

 the hydrogen and oxygen which we take in water, enter 

 into the composition of many alimentary principles by 

 being changed into the constituents of tho blood. When 

 starch or gum becomes sugar, tho transmutation is 

 effected by the absorption of water ; for, with regard to 

 their composition, a greater proportion only of water dis- 

 tinguishes sugar from starch ; and separation of oxygen 

 from sugar, causes the latter to be converted into fat. 



No alimentary principle is so easily removed from the 

 body as water, if taken in excess ; for as no decomposi- 

 tion is required in order to its being attracted by tho 

 lungs, the kidneys, the skin, and the sudoriferous glands, 

 it is not even necessary for this process that a greater 

 proportion of oxygen be taken in. Water, taken in 

 abundance, increases, at a low temperature, the activity 

 of the kidneys ; at a high oue, the perspiration. Ho, 



