that appearance so striking in Negroes. This state of the skin makes it liable to exanthematic effections, e. g. Measles, Small-pox, Syphilis, Leprosy, Elephantiasis).—In cold countries the transpiration of the skin is very weak; in consequence the internal secretions are increased in quantity, while in hot countries they are lessened from a directly opposite cause.” Comp. _J. von Röser_, “Ueber einige Krankheiten des Orients,” (On some Diseases of the East). Augsburg 1837., pp. 67-71., to whose statements we shall have to return on several future occasions. [172] _Joannes Leo_, “Descriptio Africae”, (Description of Africa), Leyden 1632. 12mo., p. 86., Paucis admodum toto Atlante, tota Numidia totaque Libya hoc notum est contagium. Quodsi quisquam fuerit qui se eo infectum sentiat, mox in Numidiam aut in Nigritarum regionem proficiscitur, cuius tanta est aeris temperies, ut optimae sanitati restitutus inde in patriam redeat: quod quidem multis accidisse ipse meis vidi oculis, qui nullo adhibito neque pharmaco neque medico, praeter saluberrimum iam dictum aërem, revaluerant. (To very few persons indeed in the whole of the Atlas, the whole of Numidia and of Libya, is this contagion known. But if there should be any man who feels himself attacked by it, he presently journeys into Numidia or the district of the Nigritae, where the nature of the air is such that he returns home again restored to excellent good health. This I have seen happen to many with my own eyes, who without help of druggist or doctor recovered by the exceeding salubrity of the air as aforesaid). Comp. _Scaliger_, Exercitat. CLXXX. ch. 18.—_Petronius_, loco citato p. 1213. [173] _Schnurrer_, “Geographische Nosologie,” (Geographical Nosology,—Distribution of Diseases), p. 454.