350 PHYSIOLOGY AND HEALTH. 



the point where the brain is fatigued, the intellect is fatigued, 

 and when the brain sleeps, the mind falls into a state of un- 

 consciousness. 



804. Whatever excites the brain excites the mind. The 

 wine that first stimulates and then oppresses the nervous 

 system, also at first quickens mental action, and then over- 

 whelms the mind with stupor. Whatever stimulating sub- 

 stance sends more blood to the brain, excites the mind to 

 quicker action, and gives it a greater grasp of thought. On 

 the contrary, whatever excites the mind to unusual action, oc- 

 casions unusual flow of blood to the brain. The arteries of 

 the brain were seen to beat ( 787, p. 343) when the passions 

 were irritated or the mind excited, and even when the sleeper 

 was troubled with dreams. The blood flows in unnatural 

 abundance through the brain of a man in passion, and of 

 the scholar while he is studying with all his mental activity. 

 The reverse happens when any emotion oppresses the mental 

 energies. When one is appalled with fear, or depressed 

 with sorrow, his countenance is pale with the absence of 

 blood, and the brain is supplied in the same imperfect 

 degree. 



805. The mind is subject to all the liabilities of the brain. 

 It shares in all its sympathies with other organs of the body. 

 When the brain is pressed with blood, as in apoplexy, or with 

 a piece of broken skull, the mind is stupid. When the head 

 : aches from breathing foul air, the mind is dull : and it is 

 torpid when one breathes charcoal gas. When alcohol 

 gently increases the flow of blood in the head, the mind is 

 more active, and the spirits more lively ; and when this flow 

 is a little more increased, and the brain stimulated too highly, 

 the mind loses its balance, the thoughts run, and the tongue 

 talks wildly ; and a still further increase of blood stupefies 

 the brain, and then the mind is torpid, and insensibility 

 follows. 



806. I lately saw a child whose brain seemed to be torpid, 

 but whose whole body was writhing in convulsions. The 

 brain was oppressed, and the child was senseless; she could 



