Every physician who has spent years of an active life in prescribing for large numbers of patients, is morally bound to publish his experience to the world, provided he is satisfied, in his interior conscience, that such a publication might be useful to the general interests of humanity.

In offering the following essay to my readers, I simply desire to fulfil an obligation recognised as valid by the inner sense. This essay contains every thing that an experience of forty years in the conscientious and philanthropic exercise of my profession has sanctioned and confirmed as truth. Nor have I adopted a single fact, suggested by my own observation, as correct, without contrasting it with the most approved records of medicine. To every true friend of man, and more particularly to every physician who considers the business of healing disease as the highest office of medical art, I offer this essay for further trial and examination. May the statements expressed in it either be confirmed or else corrected and improved by those who excel in more thorough knowledge and ability.

Berlin, Oct., 1857.