374 REPORT—1862. 
testimony is to be found, not in those differences of judgment which we 
might reasonably expect when we view it as a species of evidence embracing 
inferences as well as facts, but rather in the anomalous practice of engaging 
technical and scientific witnesses ea parte, to prove a case on either side. 
In vindication of such a practice, it may be said that there is no other 
method by which the truth can be so well elicited, and justice therefore so 
well administered. As the arguments of counsel ea parte for their respective 
clients bring out before the judge and jury all that can be alleged on either 
side in point of reasoning, so may the facts adduced in the same manner by 
professional witnesses be considered as giving a more complete view of the 
data for determining a question than if they were sought by an indifferent 
inquirer. 
This statement might be accepted as satisfactory, if professional witnesses 
were engaged to investigate facts only; but they are engaged also to deliver 
opinions ; and opinion, even in conscientious minds, is prone to follow the side 
which it is employed to support ; whilst less scrupulous witnesses are induced 
by the position in which they are placed to utter opinions different from those 
which they have been known to deliver on the same points under other 
circumstances. 
The evil of such a state of things is undeniably great, not only as regards 
the credit of honourable professions, but the public administration of the law ; 
for questions of importance are thus tried under the double disadvantage of 
testimony which can be only partially trusted, and juries who are incompetent 
to sift it, because relating to subjects with which they are little acquainted. 
Nor are these questions of rare occurrence; technical evidence has of late 
been greatly extended, in proportion to the rapid progress of the arts; and it 
must be remembered that it comprehends trades as well as professions, 
including all cases in which experts are called in to speak to facts or infer- 
ences of which persons inexperienced in the trade or profession are incapable 
of judging. So numerous and important have these cases become, that the 
evidence which affects them cannot but be considered as having gained such 
a place in our jurisprudence as to demand a careful revision of its very serious 
defects. 
For some years past, various schemes of alteration in the existing practice 
of the courts have been suggested. In a lecture delivered by Dr. Christison 
before the Edinburgh College of Physicians in 1851, and in papers read by 
Dr. Angus Smith in 1857 and subsequent years before various societies, the 
whole subject has been ably discussed; the attention of several legal and 
judicial authorities has also been drawn to it by Mr. Harcourt; and the 
Committee consider themselves as having gained sufficient information to 
perform the duty entrusted to them by the Association of “ suggesting im- 
provements in the present practice respecting scientific evidence as taken in 
Courts of Law.” : 
Any attempt to supersede the existing system, as respects the liberty of 
each party in a suit to obtain evidence for its own case on technical questions, 
whether of fact or opinion, the Committee would regard as impracticable. 
But they are of opinion that such checks on ex parte evidence might be intro- 
duced with advantage as would counteract some of its injurious tendencies, 
and would lead, in a conflict of opinions, to a better judgment on the merits 
of the case. 
In days less scientific than the present there were questions of great im- 
portance in a maritime country, the just decision of which required more 
technical knowledge than any ordinary jury could be supposed to possess. 
