"It was painful for me to grope in the dark, guided only by our books in the treatment of the sick--to prescribe according to this or that fanciful view of the nature of diseases, substances that only owed to mere opinion their place in the _Materia Medica_. I had conscientious scruples about treating unknown morbid states in my suffering fellow-creatures with these unknown medicines; which, being powerful substances, might, if they were not exactly suitable, (and how could the physician know whether they were suitable or not, seeing that their peculiar special actions were not yet elucidated?), easily change life into death, or produce new affections or chronic ailments, which are often much more difficult to remove than the original disease. To become in this way a murderer, or an aggravator of the sufferings of mankind, was to me a fearful thought. So fearful and distressing was it, that shortly after my marriage I abandoned the practice, and scarcely treated any one for fear of doing him harm." In 1789, he settled in Leipzig, and numerous writings and translations, which have been often quoted by the best writers ever since, came from his pen during that period. We come now to the year 1790, in which the first thought of Hom[oe]opathy issued from the brain of the great father and founder of the new school of medicine. It has already been hinted that Hahnemann had felt an intense desire to obtain some clear, safe and philosophical guide to the therapeutic action of drugs. He was called upon to translate "Cullen's Materia Medica," and as he progressed in the description of one medical substance after another, he could not but feel a renewal of the earnest longing he had so often cherished, to clear medical science from the clouds of mist and uncertainty in which it had continued from the time of Hippocrates. * * * * * The workings of his mind, and the character of the man, at this time will be best understood by a quotation from the letter he wrote to Hufeland, where he says: "Having briefly reviewed, the sad experience of the systems of Sydenham and Hoffmann, of Boerhave and Glaubius, of Stahl, Cullen and de Hean," he continues,