II.--Growth and Development of the Modern Methods of Chemically Detecting Poisons. § 8. The history of the detection of poisons has gone through several phases. The first phase has already been incidentally touched upon--_i.e._, detection by antecedent and surrounding circumstances, aided sometimes by experiments on animals. If the death was sudden, if the post-mortem decomposition was rapid, poison was indicated: sometimes a portion of the food last eaten, or the suspected thing, would be given to an animal; if the animal also died, such accumulation of proof would render the matter beyond doubt. The modern toxicologists are more sceptical, for even the last test is not of itself satisfactory. It is now known that meat may become filled with bacilli and produce rapid death, and yet no poison, as such, has been added. In the next phase, the doctors were permitted to dissect, and to familiarise themselves with pathological appearances. This was a great step gained: the apoplexies, heart diseases, perforations of the stomach, and fatal internal hæmorrhages could no longer be ascribed to poison. If popular clamour made a false accusation, there was more chance of a correct judgment. It was not until the end of the eighteenth and the beginning of the present century, however, that chemistry was far enough advanced to test for the more common mineral poisons; the modern phase was then entered on, and toxicology took a new departure. § 9. From the treatise of Barthélémy d’Anglais[17] in the thirteenth century (in which he noticed the poisonous properties of quicksilver vapour), up to the end of the fifteenth century, there are numerous treatises upon poison, most of which are mere learned compilations, and scarcely repay perusal. In the sixteenth century, there are a few works, such, for example, as Porta, which partook of the general advancement of science, and left behind the stereotyped doctrine of the old classical schools.[18] [17] _De Rerum Proprietaribus._ [18] In the sixteenth century it was not considered proper to write upon poisons. Jerome Cardan declared a poisoner worse than a brigand, “and that is why I have refused not only to teach or experiment on such things, but even to know them.”--_J. Cardan: De Subtilitate_. Basel, 1558. In the seventeenth century the Honourable Robert Boyle made some shrewd observations, bearing on toxicology, in his work on “The usefulness of Natural Philosophy,” &c.: Oxford, 1664. Nicolas L’Emery also wrote a _Cours de Chimie_,--quite an epitome of the chemical science of the time.[19] [19] _Cours de Chimie, contenant la manière de faire les opérations qui sont en usage dans la Médecine._ Paris, 1675.