456 REPORT — 1866. 



JReport of the Committee on Scientific Evidence in Courts of Laiv, con- 

 sisting of the Rev. W. Y, Harcourt, Professor Williamson, the 

 Eiglit Hon. J. Napier, Mr. W. Tite, Professor Christison, Mr. 

 Carpjiael, Dr. Tyxdall, Mr. James Heywood, Mr. J. F. Bate- 

 man, Mr. Thomas Webster, Sir Benjamin Brodie, Bart., and 

 Profcs.sor W. A. ]Miller : Professor Williamson, Secretary. 



Tx the year 1S62 a Committee of this Association recommended that " By a 

 Legislative Act judges sliould be empo^rcred, on application from a suitor,' in 

 causes of a technical character, to convene skilled assessors, the number of 

 whom should not exceed three, and -who should give their opinions truly 

 on the statements of the witnesses in such manner as they shall be required 

 by the judge previous to his adjudication of the cause." No legislative action 

 has, however, as yet been taken upon this recommendation. 



It is admitted that the character and functions of one class of witnesses have 

 of late years undergone an important development, which has removed them 

 from the position of ordinary witnesses. Yet no provision has as yet been made 

 for this alteration, and the new witnesses are in the eyes of the law stUl like 

 other witnesses. These new witnesses may be described as active witnesses ; 

 for the novelty in their functions consists in the practice of collecting by 

 active exertions facts which are favourable to one conclusion upon the question 

 at issue, and even making experimental researches for the discovery of new 

 facts which may be favourable to that side. An impartial witness goes into 

 court to depose to such facts as he may know pertaining to the question under 

 investigation, and he is bound to state tliose facts in ;is accurate and straightfor- 

 ward a manner as possible, and to avoid shaping his statements with a view of 

 promoting one conclusion or verdict more than another. But an active wit- 

 ness, wiieii he undertakes to give e\-idence iipon any question, need not be 

 possessed of any specific information bearing upon the question at issue. He 

 receives statements and information from persons who are interested in one par- 

 ticular conclusion, and he receives no information from the opposite party. 

 But with his mind thus prepared with facts on one side of the question, he 

 frequently sets to work to verify these facts experimentally, or to find new 

 facts bearing upon the question at issue. His opportunities of collecting facts 

 for the trial are one-sided, and his facts arc mainly in favour of one particular 

 view of the case — the view which he has been employed to sujiport. So 

 well is this partiality of the evidence of scientific witnesses felt and acknow- 

 ledged, that the more conscientious witnesses, and probably most scientific wit- 

 nesses, would decline to give evidence at the request of a party whose case they 

 considered unjust. They know that their efforts would tend to increase his 

 chances of success, and they decline to promote a cause which they consider 

 unjust. By thus acting, these conscientious witnesses usurp the functions of 

 judge : for they decide the case in their own minds, and either strive to carry 

 out what they consider a just conclusion, or refuse to aid what they consider an 

 imjust one. If his position in a trial were not of necessity one-sided, and if 

 he did not consider himself bound to support the side \ipon which he is 

 employed, a scientific or active v^■itncss would have no motive for forming an 

 opinion upon the subject at issue before consenting to give evidence. His verj- 

 selection of what seems the time side is a proof that he is aware of being 

 necessarily partial. AVith our present procechn-*, every scientific witness must 

 cither allow clianccto decide Avhich side he will aid by his exertions, or else he 

 must prejudge in his own mind the (lucstion at issue, and then strive to carry 



