520 PRACTICE OF PHYSIC. 



MDLIV. It is indeed further asserted, that in many in- 

 stances of insane persons, their brain had been examined after 

 death without showing that any organic lesions had before sub- 

 sisted in the brain, or finding that any morbid state of the brain 

 then appeared. This, no doubt, may serve to show, that or- 

 ganic lesions had not been the cause of the disease ; but it does 

 not assure us that no morbid change had taken place in the brain : 

 for it is probable, that the dissectors were not always aware of 

 its being the general condition of hardness and density, as dif- 

 ferent in different parts of the brain, that was to be attended to, 

 in order to discover the cause of the preceding disease ; and 

 therefore many of them had not with this view examined the 

 state of the brain, as Morgagni seems carefully to have done. 



MDLV. Having thus endeavoured to investigate the cause 

 of insanity in general, it were to be wished that I could apply the 

 doctrine to the distinguishing the several species of it, accord- 

 ing as they depend upon the different state and circumstances of 

 the brain, and thereby to the establishing of a scientific and ac- 

 curately adapted method of cure. These purposes, however, 

 appear to me to be extremely difficult to be attained ; and I 

 cannot hope to execute them here. All I can do is to make some 

 attempts, and offer some reflections, which further observation, 

 and greater sagacity, may hereafter render more useful. 



MDLVI. The ingenious Dr. Arnold has been commendably 

 employed in distinguishing the different species of insanity as 

 they appear with respect to the mind ; and his labours may 

 hereafter prove useful, when we shall come to know something 

 more of the different states of the brain corresponding to these 

 different states of the mind ; but at present I can make little 

 application of his numerous distinctions. It appears to me that 

 he has chiefly pointed out and enumerated distinctions that are 

 merely varieties, which can lead to little or no variety of prac- 

 tice : and I am especially led to form the latter conclusion, be- 

 cause these varieties appear to me to be often combined together, 

 and to be often changed into one another, in the same person ; 

 in whom we must therefore suppose a general cause of the dis- 

 ease, which, so far as it can be known, must establish the pa- 

 thology, and especially direct the practice. 



MDLVII. In. my limited views of the different states of 



