30 



ANIMAL CHEMISTRY. 



combined, in the form of urea, 3 oz., and in 

 the form of hippuric acid, 3 oz. of carbon. 

 Without going further into the calculation 

 it will readily be admitted, that the volume 

 of air inspired and expired by a horse, the 

 quantity of oxygen consumed, and, as a 

 necessary consequence, the amount of car- 

 bonic acid given out by the animal, is much 

 greater than in the respiratory process in 

 man. But an adult man consumes daily 

 about 14 oz. of carbon, and the determination 

 of Boussingault, according to which a 

 horse expires 79 oz. daily, cannot be very far 



from the truth. 



In the nitrogen ized 



constituents of his 



food, therr/bre, the horse receives rather less 

 than the fifth part of the carbon which his 

 organism requires for the support of the re- 

 spiratory process ; and we see that the wis- 

 dom of the Creator has. added to his food 

 the ths which are wanting, in various 

 forms, as, starch, sugar, &c. with which the 

 animal must be supplied, or his organism 

 will be destroyed by the action of the oxygen. 



It is obvious, that in the system of the gra- 

 minivora, whose food contains so small a 

 proportion, relatively, of the constituents of 

 blood, the process of metamorphosis in ex- 

 isting tissues, and consequently their resto- 

 ration or reproduction, must go on far less 

 rapidly than in the carnivora. Were this 

 not the case, a vegetation a thousand times 

 more luxuriant than the actual one would 

 not suffice for their nourishment. Sugar, 

 gum, and starch would no longer be neces- 

 sary to support life in these animals, be- 

 cause, in that case, the products of the 

 waste, or metamorphosis of the organized 

 tissues, would contain enough of carbon to 

 support the respiratory process. 



Man, when confined to animal food, re- 

 quires for his support and nourishment ex- 

 tensive sources of food, even more widely 

 extended than the lion and tiger, because, 

 when he has the opportunity, he kills with- 

 out eating. 



A nation of hunters, on a limited space, 

 is utterly incapable of increasing its num- 

 bers beyond a certain point, which is soon 

 attained. The carbon necessary for respira- 

 tion must be obtained from the animals, of 

 which only a limited number can live on the 

 space supposed. These animals collect from 

 the plants the constituents of their organs 

 and of their blood, and yield them, in turn, 

 to the savages who live by the chase alone. 

 They, again, receive this food unaccompa- 

 nied by those compounds, destitute of nitro- 

 gen, which, during the life of the animals, 

 served to support the respiratory process. 

 In such men, confined to an animal diet, it 

 is the carbon of the flesh and of the blood 

 which must take the place of starch and 

 sugar. 



But 151bs. of flesh contain not more car- 

 bon than 4 Ibs. of starch, (16) and while the 

 savage with one animal and an equal weight 

 of starch could maintain life and health for 

 a certain number of days, he would be com- 



pelled, if confined to flesh/in order to pro- 

 cure the carbon necessary for respiration, 

 during the same time, to consume five such 

 animals. 



It is easy to see, from these considerations, 

 how close the connexion is between agricul- 

 ture and the multiplication of the human 

 species. The cultivation of our crops has 

 ultimately no other object than the produc- 

 tion of a maximum of those substances 

 which are adapted for assimilation and re- 

 spiration, in the smallest possible space. 

 Grain and other nutritious vegetables yield 

 us, not only in starch, sugar, and gum, the 

 carbon which protects our organs from the 

 action of oxygen, and produces in the or- 

 ganism the heat which is essential to life, 

 but also in the form of vegetable fibrine, al- 

 bumen, and caseine, our blood, from which 

 the other parts of our body are developed 



Man, when confined to animal food, re- 

 spires, like the camivora, at the expense of 

 the matters produced by the metamorphosis 

 of organized tissues ; and, just as the lion, 

 tiger, hyaena, in the cages of a menagerie, 

 are compelled to accelerate the waste of the 

 organized tissues by incessant motion, in or- 

 der to furnish the matter necessary for re- 

 spiration, so the savage, for the very same 

 object, is forced to make the most laborious 

 exertions and go through a vast amount of 

 muscular exercise. He is compelled to con- 

 sume force merely in order to supply mat- 

 ter for respiration. 



Cultivation is the economy of force. Sci- 

 ence teaches us the simplest means of ob- 

 taining the greatest effect with the smallest 

 expenditure of power, and with given 

 means to produce a maximum of force. The 

 unprofitable exertion, of power, the waste of 

 force in agriculture, in other branches of in- 

 dustry, in science, or in social economy, is 

 characteristic of the savage state, or of the 

 want of cultivation. 



XV. A comparison of the urine of the 

 carnivora with that of the graminivora 

 shows very clearly, that the process of meta- 

 morphosis in the tissues is different, both in 

 form and in rapidity, in the two classes of 

 animals. 



The urine of carnivorous animals is acid, 

 and contains alkaline bases united with uric, 

 Dhosphoric, and sulphuric acids. We know 

 3erfectly the source of the two latter acids. 

 All the tissues, with the exception of cellular 

 tissue and membrane, contain phosphoric 

 cid and sulphur, which latter element is 

 converted into sulphuric acid by the oxygen 

 f the arterial blood. In the various fluids 

 f the body there are only traces of phos- 

 )hates or sulphates, except in the urine, 

 where both are found in abundance. It is 

 ?lain that they are derived from the meta- 

 morphosed tissues; they enter into the ve- 

 ious blood in the form of soluble salts, and 

 ire separated from it in its passage through 

 he kidneys. 



The urine of the graminivora is alkaline; 

 t contains alkaline carbonates in abundance, 



