Only after all this has been systematically and sufficiently analyzed, will it become possible to trace the development and course of the Disease itself and to mark the successive changes offered to observation from its first appearance to the time when its history was recorded. Now these changes are imposed upon it either by its own proper nature or from outside, and so the Historian must explain also the internal and external relations involved. Again in any individual case the various manifestations or signs of a Disease by no means appear all together at one time, but rather develope in a series; so in the _general_ course of a Disease, as recorded historically, a similar continuous series of symptoms will be more or less clearly noticeable, yet without implying that it is dependent solely on external conditions. Further, as every Disease is liable at any given time to come into conflict with another, the Historian will in this case also have to point out, what forms the relations of either took at the moment, whether the disease in question showed itself as determining the other or was itself determined by it, whether it consented to enter into combinations, whether it led to the annihilation of its adversary or was itself annihilated, or whether lastly both remained in a manner neutral. Finally account must be taken of the influence of medical aid, and generally of the relation of the Physician to the Disease. These different points once successfully and in a competent manner co-ordinated into a kind of organic connexion, the resulting History of Disease, a clinical History, yet as wide as humanity itself, will supply the most momentous factor towards an insight into the nature and essence of Disease. It will not merely afford the theoretical enquirer the necessary materials for his speculations as to Disease in general and systems of treatment, but also teach the practical Physician the conditions of a rational method of Therapeutics; and will consequently be equally interesting, and what is more, equally needful to both. Such an organic connexion can only be established on the condition that the Historian calls to remembrance step by step, as he proceeds, the sciences of Physiology and Pathology. Only by their help is it possible always and everywhere to mark the inner necessity of the relation of cause and effect and to distinguish the essential from the accidental. Possibility of the History of a Disease in General and of Venereal Disease in Particular.