566 PRACTICE OF PHYSIC. 



able than through the course of this disease ; but here the im- 

 petus of the blood does not appear to be considerably increased ; 

 so that I consider this headach as a little uncertain. But when, 

 after the cold fit of an Intermittent is over, the heat has re- 

 turned, then the suffusion of the face, the throbbing of the 

 temples, the sensibility to light and noise, all shew the headach 

 to be certainly a mark of the increased determination of the blood 

 towards the head. 



" Another symptom which is to be put upon the same foot- 

 ing, is a constant waking, perhaps for some nights and days 

 together. There may be irritations which affect the nervous 

 system purely, and may be the foundation of this ; but as the 

 ordinary impetus of the blood in the vessels of the head is the 

 chief means of supporting the excitement of the brain, so an in- 

 crease of it may oppose the collapse which is necessary for 

 sleep. I do not know, accordingly, of a more certain symptom 

 than constant waking, as expressing a particular determination 

 to the vessels of the head. (Physiology, CXXIX.) 



" To this head we refer also a phrenitic delirium. This, like 

 headach and waking, has various and seemingly opposite causes ; 

 but I have hinted (Physiology, p. 146, First Lines, XLV.) 

 that it always depends upon an inequality of the excitement in 

 the different parts of the sensorium, and may therefore either 

 be from the increased impetus in the vessels of the brain, or it 

 may occur with the ordinary impetus of the blood, the causes of 

 collapse taking place at the same time. But we may determine 

 this case pretty well, as our courage, active passions, anger in 

 particular, and a disposition to it, or an irascibility of temper, 

 are commonly in proportion to the impetus of the blood in the 

 vessels of the brain ; therefore the determination to the brain is 

 attended with impetuosity, with anger or direct furor, or what 

 all authors call phrenitic delirium. Ambiguities do occur up- 

 on this subject ; for, when I can observe this delirium to a cer- 

 tain degree, with great restlessness, quick talking, an angry tone, 

 easily provoked, and this amounting often to outrage and violence, 

 I must suspect that there is an increased impetus of the blood , 

 but when I see, at the same time, that this passes off very soon, 

 and that the disease goes on with more tranquillity, and ends 

 with health in no long time after, I cannot believe that any 



