INDEX. 109 



the intellectual powers, 278. Nerves crossing, 272. Divergent and con- 

 vergent fibres, 280. Cerebral circulation, 28 1 . Arterial blood retarded, 



281. Jugular veins, 282. Connexion of the action of the brain and heart, 



282. Theory of syncope, 284. Motions of the brain, 286. Experiments, 

 290. Action of the nerves and brain, 293. Principle of motion and sen- 

 sation, 294. Different intellectual functions of different parts of the brain, 

 295. Not yet perfectly understood, 295. 



Analysis of the understanding, 295. Perception, 296. Reasoning and 

 instinct, 297. Generation of the faculties, 298. Sensation, perception, 

 attention, memory, imagination, association of ideas, comparisons, judg- 

 ment, reasoning, 299. Influence of signs on the faculties of thought, 300. 

 Analysis of ideas, by M. Destutt Tracy, 302. Derangement of the mind, 

 302. Mania, 303. Idiotcy, 303. 



Of the passions, 303-T-304. State of the intellectual powers connected 

 with them, 305. Effects on the animal enconomy, 306. Of sleep and 

 waking, 307. Repose of the functions which connect us with surround- 

 objects ; condition of the functions of assimilation, during sleep, 308. 

 Proximate cause of sleep, 310 311. Of dreams and somnambulism, 

 313. Animals are also subject to dreams, 313. 



CHAPTER VIII. 



On Motions^ 3 1 4. 



This chapter treats only of voluntary motions, whose organs may be 

 distinguished into active and passive (the bones and muscles,) 3 1 4. Struc- 

 ture and properties of muscular fibres, 315. Of the tendons and aponeu- 

 roses, 316. Phenomena of muscular contraction determined by an act 

 of the will, 317. A sound state of the nerves, arteries, and veins belong- 

 ing to a muscle is necessary to its action, 317. Theory of this action, 

 318. Preponderance of the flexor muscles over the extensors, 318. 

 The preponderance varies, according to the age, in the state of health 

 or disease, 319. Of the power of the muscles ; it bears a proportion to 

 the number of their fibres, 32 1 . The degree of shortening of which they 

 are capable is proportioned to the length of their fibres, 323. Direction 

 of the motions performed by the action of the muscles, 323. Of muscu- 

 lar flesh, 324. Galvanism, 326. Volta's apparatus, or Galvanic pile, 326. 

 Effects of Galvanism, in the treatment of disease, 330. General view of 

 the osseous system, 332. Of the vertebral column ; it forms the most es- 

 sential part of the skeleton, 334. Difference of the stature at different 

 times of the day, 335. Of the lower limbs, 335. Structure of the bones, 

 336. Uses of the periosteum, and of the marrow, 338. Theory of ne- 

 crosis, 339. Of the articulations, 340. Of the articulating cartilages, 

 341. Of the synovia, 341. Theory of anchylosis, 343. 



Of animal mechanics ; of standing, 344. Of the centre of gravity, 344. 

 Tendency of the body to fall, 344 347. Standing is performed by an 

 effort of the extensor muscles, 348. Reasons why it is impossible for a 

 new-born child to stand, 350. Man is the only animal that can stand up- 

 right, 350. Of falls, 351. Of standing on one foot, 352. A degree of 

 separation of the feet necessary in standing, 352. Of kneeling 5 of sit- 

 ting; of the recumbent posture, 354. Of lying on the sides, 354. Of 

 the prone and supine postures, 355. The different modes of recumbent 

 posture have a reference to the degrees of facility of respiration and to 



