190 APPENDIX. 
liberty which is usually conceded in cases of importance. 
Whatever may be the importance of a case to a prisoner, 
‘nothing can justify the putting of questions in a loud and 
insulting tone to a skilled professional witness. The very 
mild rebuke administered to counsel on this occasion was 
not likely to produce much effect, and accordingly this trial 
presents, in a concentrated form, all the defects of our 
method of getting at truth by cross-examination. The 
result is seen in the unsatisfactory nature of the verdict, 
which was against the medical and general evidence in the 
case. 
Witness should be Master of his Subject, and 
clear in his own Mind. 
However anxious an incompetent witness may be to ap- 
pear learned, and however hard he may labour to show it, 
he will ever find it a difficult business to make the Court 
and counsel believe that he is really so. To appear really 
learned he must be able to make the subject on which he 
gives an opinion c/ear, and to give satisfactory reasons for 
this opinion. He must be not only a thinker, but must 
satisfy others that he is master of the subject. Take almost 
any one of the important scientific questions upon which a 
professional witness is called to pass an opinion, and unless 
he has looked at the subject before with a purpose to under- 
stand <t—comprehending its extent, weight, and relations— 
he will find it to have suddenly assumed an importance he 
has not suspected, just at the time when the discovery will 
add to his confusion. It is better to make this discovery 
in the quiet stillness and security of solitude, than under 
the eye of a judge and the severe scrutiny of counsel. A 
man, whether learned or not—whether in court or out of 
court—will talk clearly upon a subject he well understands, 
whether it is scientific or otherwise; but waess it zs. clear 
