Note 66 — Chapter II

The evidence of an universal connexion in the animal frame between exertion and decay, is now almost complete. In regard to the muscular system, see Carpenter's Human Physiology, pp. 440, 441, 581, edit. 1846: ‘there is strong reason to believe the waste or decomposition of the muscular tissue to be in exact proportion to the degree in which it is exerted.’ This perhaps would be generally anticipated even in the absence of direct proof; but what is more interesting, is that the same principle holds good of the nervous system. The human brain of an adult contains about one and a half per cent of phosphorus; and it has been ascertained, that after the mind has been much exercised, phosphates are excreted, and that in the case of inflammation of the brain their excretion (by the kidneys) is very considerable. See Paget's Lectures on Surgical Pathology, 1853, vol. i. pp. 6, 7, 434; Carpenter's Human Physiology, pp. 192, 193, 222; Simon's Animal Chemistry, vol. ii. p. 426; Henle, Anatomie Générale, vol. ii. p. 172. The reader may also consult respecting the phosphorus of the brain the recent very able work of MM. Robin et Verdeil, Chimie Anatomique, vol. i. p. 215, vol. ii. p. 348, Paris, 1853. According to these writers (vol. iii. p. 445), its existence in the brain was first announced by Hensing, in 1779.