Page:Travels to Discover the Source of the Nile - In the Years 1768, 1769, 1770, 1771, 1772, and 1773 volume 3.djvu/67

Rh ferior to the finest Spa. Drink largely of this without fear, according as your appetite requires. By violent perspiration the aqueous part of your blood is thrown off; and it is not spiritous liquor can restore this, whatever momentary strength it may give you from another cause. When hot, and almost fainting with weakness from continual perspiration, I have gone into a warm bath, and been immediately restored to strength, as upon first rising in the morning. Some perhaps will object, that this heat should have weakened and overpowered you; but the fact is otherwise; and the reason is, the quantity of water, taken up by your absorbing vessels, restored to your blood that finer fluid which was thrown off, and then the uneasiness occasioned by that want ceased, for it was the want of that we called uneasiness.

Nubia never scruple to throw yourself into the coldest river or spring you can find, in whatever degree of heat you are. The reason of the difference in Europe is, that when by violence you have raised yourself to an extraordinary degree of heat, the cold water in which you plunge yourself checks your perspiration, and shuts your pores suddenly. The medium is itself too cold, and you do not use force sufficient to bring back the perspiration, which nought but action occasioned; whereas, in these warm countries, your perspiration is natural and constant, though no action be used, only from the temperature of the medium; therefore, though your pores are shut, the moment you plunge yourself in the cold water, the simple condition of the outward air again covers you with pearls of sweat the moment you emerge; and you begin the expence of the aqueous part of your blood afresh from the new stock that you have laid in by your immersion.