who had given a lifetime of study to this particular subject. On the
trial of Madeleine Smith, Professor Christison--at that time the first
toxicologist of England--stated that if in any case the symptoms and
post-mortem appearances corresponded exactly with those caused by
arsenic, he should be led to _suspect_ poisoning.

Another source of mischief lies in the fact that the law does not
recognize the well-established principles of forensic medicine, and
consequently the books in which these principles are laid down by the
highest authorities are excluded by the courts, while the _vivâ voce_
evidence of any medical man, however ignorant on such points, is
admitted as that of an expert.

It is therefore not to be wondered at that juries give but little
consideration to the knowledge or professional standing of expert
witnesses. It is, in fact, notorious that the medical autocrat of the
village, who has superintended the entrance of the majority of the
jurymen into this troublous world, is a more important witness than
the most renowned special student of the branch: indeed, the chief
value of the real expert often rests on his ability to influence the
local physician.[14] At the late Wharton-Van Ness trial the defence
desired to show that the work of the chemist employed by the
prosecution was unreliable, because the analyses made by him in a
previous case had "been condemned by the united voice of the whole
scientific world." The court was not able to see the _relevancy_ of
this, and refused to allow the professional ability or standing of an
expert to be called in question. The witness thus adjudged competent
brought no results into court; had kept no laboratory notes; relied
solely on a memory so deficient that although he had been teaching for
thirty-five years, he could not tell the shape of a crystal of tartar