Chap. III. ACTIOX OF THE NERVOUS SYSTEM. SI 



All this reacts on the brain, and prostration soon 

 follows with collapsed muscles and dulled eyes. As 

 associated habit no longer prompts the sufferer to action, 

 he is urged by his friends to voluntary exertion, and 

 not to give way to silent, motionless grief. Exertion 

 stimulates the heart, and this reacts on the brain, and 

 aids the mind to bear its heavy load. 



Pain, if severe, soon induces extreme depression or 

 prostration: but it is at first a stimulant and excites to 

 action, as we see when we whip a horse, and as is shown 

 bv the horrid tortures inflicted in foreign lands on ex- 

 hausted dray-bullocks, to rouse them to renewed exertion. 

 Fear again is the most depressing of all the emotions: 

 and it soon induces utter, helpless prostration, as if in 

 consequence of, or in association with, the most violent 

 and prolonged attempts to escape from the danger, 

 though no such attempts have actually been made. 

 Nevertheless, even extreme fear often acts at first as a 

 powerful stimulant. A man or animal driven through 

 terror to desperation, is endowed with wonderful 

 strength, and is notoriously dangerous in the highest 

 decree. 



On the whole we may conclude that the principle of 

 the direct action of the sensorium on the body, due to 

 the constitution of the nervous system, and from the first 

 independent of the will, has been highly influential in 

 determining many expressions. Good instances are 

 afforded bv the trembling of the muscles, the sweating 

 of the skin, the modified secretions of the alimentary 

 canal and glands, under various emotions and sensations. 

 But actions of this kind are often combined with others, 

 which follow from our first principle, namely, that actions 

 wliich have often been of direct or indirect service, under 

 certain states of the mind, in order to gratify or relieve 



