The animal takes the starch, sugar, or fat into its stomach, and draws in oxygen through its lungs. New chemical combina- tions are thus formed, undoing the work of the plant, and send- ing back to the air, from the lungs and skin, both the starch and oxygen, in the form of carbonic-acid gas and water. The same material is constantly circulating, — now floating in invisible air, now forming the substance of the growing plant, now of the moving animal, and now diffusing itself through the air ready to go its round again. It forms part of a vegetable to-day; to- morrow it is in a man's backbone; a week hence it may have passed through another plant and into another animal. In burning coal, we cause its carbon to unite with the oxygen of the air and to disappear as carbonic acid gas. The carbon returns to the atmosphere from w^hich it may have been taken millions of years ago w^hen it was appropriated by the growing plants, which, in the form of vegetable matter, were afterwards buried beneath the surface of the earth only to reappear ages subsequently in the form of fuel. The earth itself breathes out carbonic acid, sometimes with water, sometimes alone. It sparkles in the springs of Carlsbad and Seltzer; it kills man and beast in the terrible Valley of Death " in the island of Java. In this way is supplied the loss of that which is daily buried by the shell fish and coral insects in the limestone formations and coral growths. These rocks contain, chained down in seem- ingly everlasting imprisonment, two fifths of their weight of carbonic acid. Circulation of Nitrogen. — Gluten and fibrine are distinguished from starch and fat by containing nitrogen. The nitrogen forms 480 The Boston Cook Book. four fifths of the air. It exists also in ammonia, and in aqua fortis, or nitric acid. These two compound bodies exist and are found in the soil; and from the soil the nitrogen is taken up by the plants, and gluten is formed. When the animal consumes the gluten, it builds up and renews the waste of its several parts. The gluten of the plant is transformed into the flesh and tissues of the living animal. Thus the nitrogen of the soil through the plant has reached the dignity of being a part of breathing, intellectual man. Having reached this form, this restless element, nitrogen, grows weary of inactivity and moves on. Not only the living body as a whole is in constant motion, but even its minutest parts are continually active. They are like the population of a great city moving to and fro, coming and going continually, weeded out and removed every hour by deaths and departures, yet as unceasingly kept up in numbers by new in-comers, chang- ing from day to day so insensibly as to escape observation, yet so evidently that after a few years scarcely a known face can be discovered among the congregated thousands." Scarcely has the gluten of the plant been fitted comfortably to its place in the muscle, the skin, or the hair of the animal, when it begins to be dissolved again and is removed.

AI-modernized reading of the original text

The animal takes the starch, sugar, or fat into its stomach, and draws in oxygen through its lungs. New chemical combinations are thus formed, undoing the work of the plant, and sending back to the air, from the lungs and skin, both the starch and oxygen, in the form of carbonic-acid gas and water. The same material is constantly circulating, — now floating in invisible air, now forming the substance of the growing plant, now of the moving animal, and now diffusing itself through the air ready to go its round again. It forms part of a vegetable to-day; tomorrow it is in a man's backbone; a week hence it may have passed through another plant and into another animal. In burning coal, we cause its carbon to unite with the oxygen of the air and to disappear as carbonic acid gas. The carbon returns to the atmosphere from which it may have been taken millions of years ago when it was appropriated by the growing plants, which, in the form of vegetable matter, were afterwards buried beneath the surface of the earth only to reappear ages subsequently in the form of fuel. The earth itself breathes out carbonic acid, sometimes with water, sometimes alone. It sparkles in the springs of Carlsbad and Seltzer; it kills man and beast in the terrible Valley of Death " in the island of Java. In this way is supplied the loss of that which is daily buried by the shell fish and coral insects in the limestone formations and coral growths. These rocks contain, chained down in seemingly everlasting imprisonment, two fifths of their weight of carbonic acid. Circulation of Nitrogen. — Gluten and fibrine are distinguished from starch and fat by containing nitrogen. The nitrogen forms 480 The Boston Cook Book. four fifths of the air. It exists also in ammonia, and in aqua fortis, or nitric acid. These two compound bodies exist and are found in the soil; and from the soil the nitrogen is taken up by the plants, and gluten is formed. When the animal consumes the gluten, it builds up and renews the waste of its several parts. The gluten of the plant is transformed into the flesh and tissues of the living animal. Thus the nitrogen of the soil through the plant has reached the dignity of being a part of breathing, intellectual man. Having reached this form, this restless element, nitrogen, grows weary of inactivity and moves on. Not only the living body as a whole is in constant motion, but even its minutest parts are continually active. They are like the population of a great city moving to and fro, coming and going continually, weeded out and removed every hour by deaths and departures, yet as unceasingly kept up in numbers by new in-comers, changing from day to day so insensibly as to escape observation, yet so evidently that after a few years scarcely a known face can be discovered among the congregated thousands." Scarcely has the gluten of the plant been fitted comfortably to its place in the muscle, the skin, or the hair of the animal, when it begins to be dissolved again and is removed.

Mrs. Lincoln's Boston cook book