"The purpose of this work is, of necessity, imperfectly represented by its title page. No sentence of moderate length would have expressed the whole scope of the inquiry; a few prefatory words are therefore particularly needed, in order that the reader may appreciate the objects aimed at. These objects are two-to destroy and to reconstruct; or rather to show, in some degree, how reconstruction may be possible in the future. The historical chapter on the origin of the doctrine of stimulus makes no attempt at an exhaustive treatment of its subject, my only aim being to prove clearly that the source of the Vitalistic notions on which our classification of remedies is based is to be found in certain metaphysical theories. The dynamical terms which many modern writers employ ought not to be permitted to deceive us; they are, in fact, but the artificial clothing of a mode of research which is unconsciously but purely metaphysical, and, as such, extremely unfitted for. the purposes of the physiologist or the physician. It is the mixture of a phraseology based on this kind of speculation with a perfectly skeptical empiricism in practice, which has brought the science of therapeutics into the extraordinary state of confusion in which we see it at the present day. It is the profound conviction that a complete review of our principles of classification is necessary, if experimental inquiry is to bring us any advantage, which has induced me to write the first two hundred and forty pages of the present volume"--Preface. (PsycINFO Database Record (c) 2010 APA, all rights reserved).