It is curious to observe that, in the warm climates of the coast, cold is the exciting cause of most of the diseases which present themselves, such as catarrh, phthisis, bowel complaints, rheumatism, and even the intermittent and remittent fevers; for we believe that the baneful influence of malaria would not be nearly so often experienced, were its operation in the developement of fever not aided by some check to the perspiration, or what the natives call _resfrio_. It is a subject of remark on the sugar estates of Cañete, and other parts of the coast, that the slave population, though they work in the humid cane-fields, are yet by no means so liable to ague as either the white man or Indian. One reason for this difference appears to be that the sebaceous glands of the dark races, and especially the negro, keep their skin smooth and soft with a supply of unctuous or oily matter, of rather offensive odour, but admirably fitted to guard against the evil effects of atmospherical vicissitudes. As black surfaces radiate heat better than those of lighter tints, it might be expected that the body of the negro would be excessively chilled when exposed to the night air: but the negroes of the coast of Peru often sleep in the open air, without interrupting the healthy action of the dermal system. This is a fact which we are disposed to refer to the preservative effect of the unctuous exudation, because all oily matters being bad conductors prevent the excessive radiation of internal, and the too rapid communication of external heat; and therefore, by this natural inunction of the negro and zambo skin, nature provides a remedy against the extremes of cold or heat under ordinary circumstances. We thus learn that flannels or woollens, being bad conductors, are, when worn next the skin, very valuable as preservatives of an equal circulation, and therefore of general health, particularly for the European of finer and unanointed skin when subjected to the influence of tropical climates. During the hot months of January and February, on the coast of Peru, the irritability of the whole system is increased, and particularly of the mucous membrane of the alimentary passages; and cholera morbus thus becomes an exceedingly common disease, for which the standard remedy is ice, or iced water. The privilege of selling ice in the capital of Peru belongs to the government, who usually let it out for a term of years to the highest bidder. The empresario, or lessee, conveys the ice on mules from the nearest snow-clad mountains at the back of Lima; and is bound to have always on hand a sufficient quantity for the supply of the capital, and be ready to deliver it at all hours of the day and night. In form of frescos, or cooling drinks, every one uses ice in warm summer weather; and it is considered not merely a luxury or a remedy, but a necessary of life, indispensable for the due preservation of the public health.