MEAD. 157 in order to establish the utility of sucking the wounds inflicted by serpents. He laboured to discover a specific for the cure of hydrophobia, and has only added his great name to the long catalogue of failures. He alludes to the investiga- tion of some chemical substances, whose publica- tion might have been injurious to society ; this was neither a vain insinuation, nor a groundless fear, in the age in which Mead lived, when secret poisoning had attained a fatal perfection in some parts of Europe, and when the infant state of che- mical science had not yet revealed the numerous tests which we now possess for detecting the pre- sence of poison. Whatever may be the merit of these Essays, their author afforded a noble instance of candour, when, forty years afterwards, he re- tracted, in a second edition, not a few of his former opinions, acknowledging, that " in some facts he had been mistaken, and in some con- clusions too precipitate." In his younger days he had believed that he could account, mechani- cally, for the effects of several poisons, by their mixture with the blood ; but, improved by age and experience, he became convinced, that, in all liv- ing creatures, a matter, infinitely more subtile, exists, over which poisons possess a real, although inexplicable, power. His second work attempted to illustrate the In- fluence of the Sun and Moon upon Human Bo- dies; but, as the Journal des Sgavans of the time says, " the particular merit of this book is, that, independently of the system, we find it filled with a number of observations of great importance in the practice of medicine." .