Moreover, the whole drift of modern medicine is toward a division of labor, and forensic medicine is more widely separated from the ordinary specialties of the science than these are from one another. In a case of delicate eye-surgery who would value the opinion of a man whose attention had been devoted mainly to thoracic diseases? What specialist of the latter character would even offer an opinion? Yet physicians who acknowledge that they have paid no especial attention to toxicology do not hesitate to give the most positive opinions upon the most delicate questions of that science. Men who would, as in honor bound, ask for a consultation in any case of serious sickness outside of their line of private practice, on the witness-stand put forth with the utmost boldness their ignorant crudities, careless or forgetful of the fact that they may be imperiling the life of an innocent human being. On the trial of Mrs. Wharton for the attempted murder of Mr. Van Ness, Dr. Williams asserted that there are peculiar characteristic symptoms or groups of symptoms of tartar emetic poisoning;[13] and both he and Dr. Chew--who with frankness acknowledged that he had not especially studied toxicology--did most positively recognize tartar emetic as the sole possible cause of certain symptoms which were but a little beyond the line of medicinal action, and for which obviously possible natural cause existed. Contrast these bold opinions with the cautious statement of a man 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.