FEVERS. 589 



" I propose, therefore, here to mention what the circumstances 

 are which express a combination of irritation and debility^ 

 particularly as the irritation occurs in the brain, and gives a sus- 

 picion of those topical affections which after death we find to 

 have truly happened, though symptoms of the inflammatory 

 state had not happened to appear before. 



" Now, one symptom of such an irritation applied to the 

 brain and nervous system, is an increased sensibility to light 

 and noise, while other symptoms of irritation do not appear to 

 affect the sanguiferous system. Any degree of inflammation in 

 the retina, by increasing the tension of the vessels which are so 

 intimately connected with the medullary fibres, must give a very 

 singular sensibility (Physiology, LVI. 3.). If, therefore, these 

 marks of sensibility appear in the organs of seeing, and also in 

 the organs of hearing, where I presume they are to be explain- 

 ed in the same manner, they are to be imputed to a preternatural 

 fulness and distention, or to an increased impetus in the vessels 

 of the eye, while at the same time there is no fulness or hard- 

 ness of the pulse, nor any considerable redness or suffusion of 

 the face, which point out a topical affection of the blood-vessels 

 of the brain. 



" I should have observed, that though inflammatory affec- 

 tions in any particular part of the system, do commonly pro- 

 duce the diathesis over the whole, this is not universally the 

 case; for we have innumerable instances of topical affections 

 merely, which do not affect the sanguiferous system more ge- 

 nerally ; and it is a dangerous state where this takes place with 

 respect to the brain. This symptom will be rendered still 

 clearer by many vessels appearing on the adnata of the eye, 

 while in other parts there is no appearance of an inflammatory 

 distention. 



" Another symptom of irritation appearing in the system, and 

 particularly applied to the brain, is interrupted sleep. The col- 

 lapse of the brain, in which sleep consists, naturally recurs upon 

 us every twenty-four hours; and, according to the health of the 

 system, and the absence of irritations, the sleep for some time 

 is quite profound and uninterrupted. If, therefore, dreams occur, 

 or if sleep is any otherwise broken off, we can perceive that ir- 

 ritations are applied to some part or other : and disturbed sleep 



