iv PREFACE. 



mental evidence. That in so varied and so difficult a research, it may be found 

 that I have sometimes been misled, and at others erred in the interpretation of 

 facts, is no doubt to be anticipated. I began this work, however, without precon- 

 ceived views, and throughout its prosecution I have endeavored to maintain that 

 condition of mind which is wanted in experimentation, and that love of truth 

 which is the parent of rational inferences.' 



S. WEIR MITCHELL. 

 1226 Walnut St., PniLADELPniA. 



' The reader who desires further information in regard to the therapeutics of the subject, and to 

 the relative value of the various antidotes still in repute, is referred to a forthcoming paper, by the 

 author, in the North American Medico-Chirurgical Review, in which the whole subject will be con- 

 sidered from a purely medical point of view. The author takes this occasion to mention the omission 

 in the medical portion of the present essay of the composition of Bibrou's antidote. It contains five 

 drachms of bromine, four grains of iodide of potassium, and two grains of corrosive sublimate. 



