86 THE POPULAR SCIENCE MONTHLY. 



philanthropic labors, conferred such signal benefits on the insane, 

 did some disservice to medical jurisprudence when he lent the 

 weight of his authority to this doctrine, and maintained that 

 " persons of common sense, conversant with the world, and hav- 

 ing a practical knowledge of mankind, brought into the presence 

 of a lunatic, would in a short time find out whether he was or was 

 not capable of managing his own affairs " ; and the late Sir Benja- 

 min Brodie erred, I think, still more grievously when he said : 

 " It is a great mistake to suppose that this is a question (unsound- 

 ness of mind) which can be determined only by medical practition- 

 ers. Any one of common sense, and having a fair knowledge of 

 human nature, who will give it due consideration, is competent 

 to form an opinion on it ; and it belongs fully as much to those 

 whose office it is to administer the law as it does to the medical 

 profession." 



Now, it may be admitted that there was a time when medical 

 science was in its infancy, when the functions of the brain were 

 unknown, and when only metaphysical explanations of insanity 

 were attempted, at which the existence of insanity in any given 

 case might have been as correctly determined by plain, unsophis- 

 ticated men as by pretentious empirics. Further, it may be grant- 

 ed that there are an immense number of cases of insanity in which 

 the symptoms of the disease are so obvious and external, that spe- 

 cial skill, although requisite to interpret these symptoms, explain 

 their causes, predict their results, and prescribe treatment, is not 

 necessary to their identification. But, beyond all this, there are, 

 it must be maintained, cases of insanity of so obscure and subtle a 

 nature that they can only be properly identified by those who 

 have made themselves intimately acquainted with the functions 

 of the nervous system in health and disease, and who have by ex- 

 perience come to appreciate the significance of combinations of 

 mental phenomena and of concomitant bodily variations, which 

 would appear meaningless to the uninitiated. 



The fact is, that practically the utility of expert testimony in 

 insanity is acknowledged, and it is difficult to understand how it 

 could be otherwise, for all who have made only a superficial study 

 of mental diseases must perceive that there are in them little sign s 

 and symptoms, perversions of thought and derangements of bod- 

 ily functions, which would altogether escape the notice of com- 

 mon sense, but warrant an expert, founding on his experience, in 

 proclaiming that the will is reduced to impotency, and that the 

 lunatic can not control himself. There is something in the ap- 

 pearance, manner, and mode of expression of lunatics of various 

 classes which would pass unnoticed by common sense, but be 

 characteristic to those who had been accustomed to watch them 

 narrowly. There are styles of morbid thought which can not be 



