“The author commenced with some remarks on the various causes by which the actions of plants and of their products on the animal body may be modified, and on the great vagueness and uncertainty of the information at present possessed in regard to the influence of those causes which seem to arise in peculiar circumstances of vegetation, more especially climate, weather, soil, and the progress of vegetation. He then stated the sources of information on these points, namely, the curative or therapeutic action of drugs on man,—their effects on the healthy functions both of man and animals, either as medicines or as poisons,—their sensible qualities,—and their chemical analysis; and he assigned reasons for discarding the first of these from the inquiry, and for trusting, in a great measure, to the criterions derived from sensible qualities,—from the effects of poisons on the lower animals,—and from chemical analysis.