But it has been supposed that certain bodies, as glass, enamel, diamonds,[138] agates, smalt, &c. when administered in the form of powder, so lacerate the membranes of the stomach, by the sharpness of their particles, as slowly to destroy life; and upon the same principle, it has been asserted, that human hair, chopped fine,[139] constitutes the active ingredient of a slow poison frequently employed in Turkey, and that it induces, by irritation, a chronic disease resembling cancer. With respect to the danger arising from the ingestion of diamond dust, enamel powder, powdered glass, and the like, there still may be said to exist some difference of opinion. _Caldani_, _Mandruzzato_,[140] and M. _Le Sauvage_, have reported experiments made upon men and inferior animals, in which no bad consequences followed the administration of such bodies; whereas _Schurigius_[141] and _Cardanus_[142] cite instances where persons have died of ulcerations of the stomach from such causes; and this opinion receives the support of _Plouquet_,[143] _Stoll_,[144] _Gmelin_,[145] _Foderé_,[146] _Mahon_,[147] _Franck_,[148] and many others. The modern pathologist will not find much difficulty in reconciling such conflicting testimony. The experimentalist may administer mechanical substances a thousand times without producing any ill effects, while, under certain circumstances, the most trivial body may lodge in the intestines and produce death; but surely the occasional occurrence of such accidents ought not to confer the general title of _poison_ upon the substances which may happen to produce them. Having thus disposed of a considerable number of bodies, which have been classed as _slow_ poisons, we may proceed to observe that most of the other substances which have found a place in the same division, appear to us to deserve consideration under a very different head, and that we shall get rid of much obscurity by adopting the following arrangement.