This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
It will be remembered that these are tonic substances which enter essentially into the constitution of the system. The only medicines which have been satisfactorily proved to belong to this subdivision of the mineral tonics, are the preparations of iron.