Since the publication of this work, I have learnt, from a very respectable quarter, that an entire faith ought not to be given to the English collection, and that this reason, together with certain calumnies, some obscenities, and the forgery of an imperial privilege, had made the German translation be prohibited in the Empire. These motives would have determined me to suppress all that I had extracted from that work, but some considerations have induced me to preserve it, under the modification of this præ-advertisement. The first is, that some of these reasons concern only the German edition. Another is, that though there may be some facts invented, as indeed some of them plainly enough appear to carry with them a stamp of falsity, it is yet proved, that the greatest number of them are but too true. In short, a third consideration which determined me, is what I find in the above-mentioned letter of M. STEHELIN. “I have (says he) received a letter from M. Hoffman of Maestrich, in which he acquaints me of his having seen a practiser of self-pollution, who had already drawn on himself a _tabes dorsalis_, which he had, without success, attempted to cure, and the patient was afterwards cured by the remedies of the _Onania_, of which Dr. BECKERS of London is supposeably the author, and so well cured, that he has recovered his corpulence, is strong and healthy, and has four children.” The English book of _Onania_ is a perfect chaos, and the most indigested work that has been produced a long time. It is only the observations that can bear reading. All the reflections of the author, whom I could not believe a physician, are nothing but theological or moral trivialisms. I shall not extract from all this work, which is rather of the longest, any thing but a description of the most common accidents, of which the patients complain. The vivacity, the pathetic expressions of pain and repentance, which are found in a few of the letters in that book, I omit in this extract; but the want of them ought not to weaken the impression of horror which the reading of the facts themselves should inspire, as it is on the facts that the impression depends; and the readers will rather have to thank me for sparing him the perusal of a much greater number of others, without order or diction. I shall class under six heads those evils of which the English patients complain, and begin with the most grievous, those of the soul. _First._ All the intellectual faculties are weakened; the memory fails; the ideas are confused or clouded; the patients sometimes even fall into a slight degree of insanity; they are continually under a kind of inward restlessness, and feel a constant anguish, with such pangs of confidence and remorse, as make them shed tears in bitterness of heart. They are subject to giddiness; all the senses, and especially those of seeing and hearing, grow weaker and weaker; their sleep, if sleep they can, is disturbed by disagreeable or frightful dreams.