MEDICAL EXPERT TESTIMONY. 603 



MEDICAL EXPERT TESTIMONY.* 



By FKANK HASTINGS HAMILTON, M. D., 



CONSULTING STJEGEON TO BELLEVUE U03PITAL, ETC. 



FROM time to time within the last few years, and perhaps for a 

 longer period, comments have been made in the daily secular 

 press, and occasionally in the medical journals, in reference to the 

 testimony of medical experts, which were anything but flattering to 

 medical men. These comments have, in most cases, had reference to 

 their testimony as experts in cases of alleged lunacy, or in cases in- 

 volving the question of moral responsibility. They have been charged 

 with ignorance, incompetency, inconsistency, and in some cases with 

 venality. It has been said that their opinions are purchasable. 



In support of these grave charges the reader has been referred to 

 the fact that an equal number of eminent experts can usually be found 

 to testify on either side, and that in their testimony they often differ 

 from each other irreconcilably. In other cases no evidence is offered 

 to sustain the charges, except the fact that the opinions of the writer 

 and of the public differ from that of the expert. 



In what I shall have to say upon this subject I propose to confine 

 myself to those examples in which the question involved is one of men- 

 tal capacity and responsibility, as being that in which medical experts 

 have been most often and most severely criticised. To a certain extent, 

 however, you will observe that the arguments employed will apply to 

 expert testimony in any other department of medicine or of science. 



1. Medical men, whether they be specialists in the study of men- 

 tal diseases or not, in the differentiation of the class of diseases now 

 under consideration, labor under peculiar difliculties. There are many 

 mental disorders which are unaccompanied with any recognizable 

 abnormal physical conditions of the brain ; that is to say, in which 

 there are no structural lesions of the brain cognizable during life, or 

 which can be satisfactorily demonstrated in the autopsy ; and there 

 are many in which the mental alienation can not be fairly traced to 

 any lesions in any other part of the body. The number of these ex- 

 amples may hereafter be found to be smaller than is now known, but 

 for the present the fact is as I have stated. That a functional dis- 

 turbance of the brain exists in such cases is self-evident ; but for 

 augbt we know this may be due to some slight molecular, chemical, or 

 vital changes in the nerve-cells of the gray matter of the brain or of a 

 group of cells, not denoted by any peculiar physical signs during life, 

 and which can leave no possible traces after death. To cause mental 



* Being a portion of the presidential addresa on " Medical Expert Testimony, especially 

 in Cases involving the Question of Insanity," delivered before the Society of Medical Juris- 

 prudence and State Medicine (New York), January 8, 1885. 



