The human organism possessed in Southern lands yet another way of combating the enemy’s attacks, one which would seem to have escaped the notice of the Physicians of Antiquity, and which, though recognized in modern times, has yet never been at all adequately appreciated and utilized in the history of Venereal disease, viz. _the reaction exhibited by the skin in diseases of the genital organs in hot climates_. So long as authorities thought of the external skin as merely compacted of separate and distinct layers of tissue, there could not really be any question of an accurate knowledge of its functions whether under healthy or under morbid conditions. The investigations of _Breschet_ and _Roussel de Vauzène_[166] as confirmed and reinforced by _Gurlt_[167], have now taught us to understand that the skin, over and above these layers, possesses as a matter of fact,—a fact formerly only conjectured,—special organs belonging to the same class as the glands, to wit the skin, hair and sweat glands. These share amongst them the function hitherto ascribed to the skin generally, and especially bring into correlation the sympathies of the different parts, so much so that they may be said to be almost the sole and only seat of the manifold forms of skin-diseases. All this we endeavoured first to demonstrate in the series of Articles on Skin-diseases in “_Blasius’_ Handwörterbuch der Chirurgie und Augenheilkunde” (Manual of Surgery and Ophthalmology), and so pave the way for a compendious Survey of our knowledge of the Skin-diseases up to the present time. Now while the sweat-glands stand in a special connection of sympathy and antagonism with the lungs, the same correlation exists in a peculiar degree between the glands of the mucous membrane of the intestinal canal and of the genital organs on the one hand and the cutaneous glands on the other which secrete the _sebum_ or sebaceous humour. It would take us too far a-field, if we undertook in this place to enter upon a detailed explanation of this circumstance, which however is still in sore need of further clearing up. We shall content ourselves with recalling the fact that Onanists (Masturbators) not only often betray themselves by having a nose with a shiny, tallowy looking surface that comes from excessive secretion of _sebum_, but also not less frequently by their face being covered with _acne_ pustulus. One more fact we must mention is that the outbreak of _acne_ very often with girls heralds the approach of each period of menstruation, and accompanies it[168]. These are signs clearly pointing to the conclusion that stimulations of the genitals are reflected back on the glands of the skin, for _acne_ is nothing else but an affection of these glands, as we have demonstrated in the Work just mentioned.