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combination took place in the lungs; but more careful experiments have made it probable that the oxygen unites with the carbon in the circulation, and that the blood-corpuscules are the carriers of the oxygen. Compare
Liebig's Animal Chemistry, p. 78;
Letters on Chemistry, pp. 335, 336;
Turner's Chemistry, vol. ii. p. 1319;
Müller's Physiology, vol. i. pp. 92, 159. That the combination does not take place in the air-cells is moreover proved by the fact that the lungs are not hotter than other parts of the body. See
Müller, vol. i. p. 348;
Thomson's Animal Chemistry, p. 633; and
Brodie's Physiol. Researches, p. 33. Another argument in favour of the red corpuscules being the carriers of oxygen, is that they are most abundant in those classes of the vertebrata which maintain the highest temperature; while the blood of invertebrata contains very few of them; and it has been doubted if they even exist in the lower articulata and mollusca. See
Carpenter's Human Physiol. pp. 109, 532;
Grant's Comparative Anatomy, p. 472;
Elliotson's Human Physiol. p. 159. In regard to the different dimensions of corpuscules, see
Henle,
Anatomie Générale, vol. i. pp. 457–467, 494, 495;
Blainville,
Physiologie Comparée, vol. i. pp. 298, 299, 301–304;
Milne Edwards,
Zoologie, part i. pp. 54–56;
Fourth Report of British Association, pp. 117, 118;
Simon's Animal Chemistry, vol. i. pp. 103, 104; and, above all, the important observations of Mr. Gulliver (
Carpenter, pp. 105, 106). These additions to our knowledge, besides being connected with the laws of animal heat and of nutrition, will, when generalized, assist speculative minds in raising pathology to a science. In the mean time I may mention the relation between an examination of the corpuscules and the theory of inflammation which Hunter and Broussais were unable to settle: this is, that the proximate cause of inflammation is the obstruction of the vessels by the adhesion of the pale corpuscules. Respecting this striking generalization, which is still on its trial, compare
Williams's Principles of Medicine, 1848, pp. 258–265, with
Paget's Surgical Pathology, 1853, vol. i. pp. 313–317;
Jones and Sieveking's Pathological Anatomy, 1854, pp. 28, 105, 106. The difficulties connected with the scientific study of inflammation are evaded in
Vogel's Pathological Anatomy, p. 418; a work which appears to me to have been greatly overrated.
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On the amount of heat disengaged by the union of carbon and oxygen, see the experiments of Dulong, in Liebig's Animal Chemistry, p. 44; and those of Despretz, in Thomson's Animal Chemistry, p. 634. Just in the same way, we find that the temperature of plants is maintained by the combination of oxygen with carbon: see Balfour's Botany, pp. 231, 232, 322, 323. As to the amount of heat caused generally by chemical combination, there is an essay well worth reading by Dr. Thomas Andrews in Report of British Association for 1849, pp. 63–78. See also Report for 1852, Transac. of Sec. p. 40, and Liebig and Kopp's Reports on the Progress of Chemistry, vol. i. p. 34, vol. iii. p. 16, vol. iv. p. 20; also Pouillet, Elémens de Physique, Paris, 1832, vol. i. part i. p. 411.
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The law of definite proportions, which, since the brilliant discoveries by Dalton, is the corner-stone of chemical knowledge, is laid down with admirable clearness in Turner's Elements of Chemistry, vol. i. pp. 146–151. Compare Brande's Chemistry, vol. i. pp. 139–144; Cuvier, Progrès des Sciences, vol. ii. p. 255; Somerville's Connexion of the Sciences, pp. 120, 121. But none of these writers have considered the law so philosophically as M. A. Comte, Philosophie Positive, vol. iii. pp. 133–176, one of the best chapters in his very profound, but ill-understood work.
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‘Ainsi, dans des temps égaux, la quantité d'oxygène consommée par le même animal est d'autant plus grande que la température ambiante est moins élevée.’ Robin et Verdeil, Chimie Anatomique, vol. ii. p. 44. Compare Simon's Lectures on Pathology, 1850, p. 188, for the diminished quantity of respiration in a high temperature; though one may question Mr. Simon's inference that therefore the blood is more venous in hot countries than in cold ones. This is not making allowance for the difference of diet, which corrects the difference of temperature.
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‘The consumption of oxygen in a given time may be expressed by the number of respirations.’ Liebig's Letters on Chemistry, p. 314; and see Thomson's Animal Chemistry, p. 611. It is also certain that exercise increases the number of respirations; and birds, which are the most active of all animals, consume more oxygen than any others. Milne Edwards, Zoologie, part i. p. 88, part ii. p. 371; Flourens, Travaux de Cuvier, pp. 153, 154, 265, 266. Compare, on the connexion between respiration and the locomotive organs, Beclard, Anatomie Générale, pp. 39, 44; Burdach, Traité de Physiologie, vol. ix. pp. 485, 556–559; Carus's Comparative Anatomy, vol. i. pp. 99, 164, 358, vol. ii. pp. 142, 160; Grant's Comparative Anatomy, pp. 455, 495, 522, 529, 537; Rymer Jones's Animal Kingdom, pp. 369, 440, 692, 714, 720; Owen's Invertebrata, pp. 322, 345, 386, 505. Thus too it has been experimentally ascertained, that in human beings exercise increases the amount of carbonic-acid gas. Mayo's Human Physiology, p. 64; Liebig and Kopp's Reports, vol. iii. p. 359.
If we now put these facts together, their bearing on the propositions in the text will become evident; because, on the whole, there is more exercise taken in cold climates than in hot ones, and there must therefore be an increased respiratory action. For proof that greater exercise is both taken and required, compare Wrangel's Polar Expedition, pp. 79, 102; Richardson's Arctic Expedition, vol. i. p. 385; Simpson's North Coast of America, pp. 49,88, which should be contrasted with the contempt for such amusements in hot countries. Indeed, in polar regions all this is so essential to preserve a normal state, that scurvy can only be kept off in the northern part of the American continent by taking considerable exercise: see Crantz, History of Greenland, vol. i. pp. 46, 62, 338.
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See the note at the end of this chapter.
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‘The fruits used by the inhabitants of southern climes do not contain, in a fresh state, more than 12 per cent. of carbon; while the blubber and train-oil which feed the inhabitants of polar regions contain 66 to 80 per cent. of that element.’ Liebig's Letters on Chemistry, p. 320; see also p. 375, and Turner's Chemistry, vol. ii. p. 1315. According to Prout (Mayo's Human Physiol. p. 136), ‘the proportion of carbon in oily bodies varies from about 60 to 80 per cent.’ The quantity of oil and fat habitually consumed in cold countries is remarkable. Wrangel (Polar Expedition, p. 21) says of the tribes in the north-east of Siberia, ‘fat is their greatest delicacy. They eat it in every possible shape; raw, melted, fresh, or spoilt.’ See also Simpson's Discoveries on the North Coast of America, pp. 147, 404.
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‘So common, that no plant is destitute of it.’ Lindley's Botany, vol. i. p. 111; and at p. 121, ‘starch is the most common of all vegetable productions.’ Dr. Lindley adds (vol. i. p. 292), that it is difficult to distinguish the grains of starch secreted by plants from cytoblasts. See also on the starch-granules, first noticed by M. Link, Reports on Botany by the Ray Society, pp. 223, 370; and respecting its predominance in the vegetable world, compare Thomson's Chemistry of Vegetables, pp. 650–652, 875; Brande's Chemistry, vol. ii. p. 1160; Turner's Chemistry, vol. ii. p. 1236; Liebig and Kopp's Reports, vol. ii. pp. 97, 98, 122.
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The oxygen is 49.39 out of 100. See the table in Liebig's Letters on Chemistry, p. 379. Amidin, which is the soluble part of starch, contains
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