XX Contents 



a greater quantity of blood may be sent through the lungs, 

 p. 244. Nor for the cooling of the heart, p. 245. But 

 because the nitro-aerial spirits are used up in the contraction 

 of the muscles, p. 245. Muscular contraction is produced 

 by the mutual effervescence of particles of different kinds, 

 p. 245. Of what sort they are, p. 246. The motive effer- 

 vescence does not seem to arise from repugnant salts, p. 246. 

 But from the mutual agitation of nitro-aerial and saline- 

 sulphureous particles, p. 247. Why exercise makes animals 

 hot, p. 248. Why sweat is salt, p. 249. It is shown that 

 nitro-aerial particles are indeed the animal spirits, p. 250. 

 They do not seem to consist of volatile salt, p. 251. The 

 enormous amount of the air is alone equal to the supply 

 of the expended animal spirits, p. 252. On the respiration 

 of insects, p. 253. Why parts cut off from them continue to 

 live, p. 254, Why in insects the branches of the tracheae 

 terminate in the spinal marrow, p. 254. Why animals fall 

 into convulsions when deprived of air, p. 255. Whence it is 

 that strength is so much reduced in phthisis, p. 255. Why 

 the brain is disturbed in malignant fever, p. 255. Why we 

 necessarily shut our eyes when we sleep, p. 256. How light- 

 ning dissipates the animal spirits, p. 257. Why animals 

 breathe more intensely for some time after violent move- 

 ments, p. 257, Why blood drawn during convulsive 

 paroxysms quickly coagulates, p. 258. Answer to an objec- 

 tion brought against the hypothesis stated above, p. 258. 

 The sensitive soul does not seem to consist of a congeries 

 of animal spirits, p. 259. A conjecture about the sensitive 

 soul, p. 259. On the pulsation of the brain, p. 260. For 

 what end it takes place, p. 260. The respiration of the 

 brain explained, p. 260. Diverse effects are produced in 

 the body in accordance with the varying contraction of the 

 meninges, p. 260. Sneezing depends on their motion, p. 261. 

 How epilepsy and apoplexy may arise from disordered 

 motion of the dura mater, p. 261. Why oil of amber and 

 the like are of use in these diseases, p. 261. Sleep seems to 

 be caused by the interrupted motion of the meninges, p. 262. 

 Why hard work and watching bring it on, p. 262. The natural 

 functions are better carried on in sleep, p. 263. 



