When I shall publish this Second Part, if ever, will depend first on the reception of the preceding volume; secondly on whether more favourable external conditions provide the leisure that is indispensably necessary for Historical investigations of the sort, and at the same time put at my disposal a more complete literary apparatus than has hitherto been the case. For historico-medical studies in general there exists hardly a more unfavourable[1] place than Halle; and this is specially and peculiarly so with regard to epidemic diseases. As far as Venereal Disease is concerned the whole literary wealth of our University Library amounts to something like ten or twelve Works, half of which are all but worthless. I myself shrank from no expense to obtain possession of the literary helps required, and my collections, particularly on the subject of Epidemics, might boast of being not inferior to those of any private individual; yet they are quite insufficient for my purpose, so much, especially from the earlier Centuries, being no longer procurable by way of purchase. But when all that is extant in writing is procured, the business is still far from being done. I am still in want of quite a formidable array of facts that can only be the fruit of observations in more recent times. For this reason may I appeal to my elder professional brethren, and above all to the different medical Unions and Associations at home and abroad with the request that they will, whether directly or indirectly, help me to the possession of the facts in question. Such are in particular facts concerning the influence of the _Genius Epidemicus_ on the different forms or Venereal Disease, and first and foremost it behoves me to learn—_what influence Typhus manifested during the first fifteen years of this Century, particularly since 1811, in different Countries_. That such an influence, and a disastrous one, _did_ take place is evidenced not only by the 364 pp. of collected Authorities, but also by the data of the brilliant SACHS in his “Concise Dictionary of Practical Therapeutics”, II. Pt. 1. (Article: Guajac) p. 637. To my sorrow I have only just, since the appearance of the Index to that valuable Work, become acquainted with these data, which appealed to me all the more from the fact that throughout they corroborate the results reached by myself in the historical sphere.