Contents 



CHAPTER VI.— Of the Mode in which the Fibrils 

 Contract. Also, of the Motion of Contracting 



Muscles. 



The fibrils seem to be shortened by their contortion, p. 

 282. That is made plain by an example, p. 282. How 

 nitro-aerial spirit contracts the fibrils, p. 283. Why muscles 

 struck by lightning become hard, p. 284. Of the motion of 

 contracting muscles, p. 284. The contraction takes place 

 towards the more fixed end of the muscle, p. 285. Muscles 

 sometimes contract towards their insertion, p. 286. On the 

 contraction of sphincters, p. 286. 



CHAPTER vn. — Of . THE Contraction of the 

 Diaphragm. Also, of the Pulsation of the 

 Heart. Incidentally, of its Palpitation. Also, 

 OF THE Motion of Animals when they raise 

 themselves aloft. 



The diaphragm in its contraction is carried downwards 

 and outwards, p. 288. It never in inspiration descends 

 below the plane, p. 288. But sometimes in expiration, when 

 the chest is wounded, it becomes convex towards the 

 intestines, p. 289. Of the pulsation of the heart, p. 290. 

 Why the heart in systole strikes the left side of the chest, 

 p. 290. How the blood is expelled from the heart, p. 292. 

 The contraction of the right ventricle contributes to the 

 constriction of the left ventricle, p. 293. Whence palpitation 

 of the heart arises, p. 294. A noteworthy case of this, p. 

 295. How the detention of the blood in the lungs causes 

 asthma, p. 297. How jumping is produced, p. 298. The 

 opinion of Dr Willis on this subject is refuted, p. 298. It is 

 produced by the contraction of the extensor muscles, p. 299. 

 The impressed force of projectiles is nothing but motion, 

 p. 300- 



