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APPENDIX, No. IV. 



NOTICE ON THE CLIMATE OF THE WESTERN COASTS OF SOUTH AMERICA 



AND MEXICO, 



AND ON ITS EFFECTS ON THE HEALTH OF THE RESIDENTS AND OF STRANGERS. 



Extracted from a MS. Memoir on the Climate and Diseases of South America, 

 Br George Birnie, Esq. R.N. 



SURGEON OF HIS MAJESTY'S SHIP "CONWAY." 



It may be interesting to notice, briefly and 

 generally, the diseases to which Europeans will be 

 more particularly liable on visiting the western 

 coast of America. For the sake of perspicuity, 

 the coast may be divided into three parts : — The 

 first extending from Valdivia, in latitude 40° 

 South, to Coquimbo, in latitude 30° South ; the 

 second from Coquimbo to Payta, in latitude 5£° 

 South ; and the third from Payta to the Gulf of 

 California, which lies in latitude 23° North. The 

 first of these divisions comprehends nearly the 

 whole coast of Chili, inhabited by the descendants 

 of the Spaniards. Chili lies between the Pacific 

 Ocean and the Andes, and has a mean breadth of 

 about 120 miles. It is one of the most healthy 

 and delightful countries in the world ; for though 

 it borders on the torrid zone, it never suffers the 

 extreme of heat, the Andes defending it on the 

 east, and gentle breezes refreshing it from the 

 west. It possesses an equable and serene temper- 

 ature, of about 64°. It is neither afflicted by in- 

 termittent fevers nor dysenteries. Some years, 

 in the summer and autumn, there occur a few 

 cases of an ardent fever, called by the Indian 

 name of Chaoo longo, which means disease of the 

 head. This complaint, in robust subjects, is ex- 

 tremely violent and rapid in its course, but yields 

 readily to bleeding and purgatives. 



The second division, from Coquimbo to Payta, 

 embraces a line of coast of about 1 500 miles in 

 length, and 70 in breadth ; the chief characteristic 

 of which is, that no rain ever falls in all this im- 

 mense tract, and the sun is generally obscured by 

 a canopy of clouds ; in consequence, the country 

 bordering on the shore, for an indefinite breadth 

 inland, is one sterile sandy desert ; and, with the 

 exception of a few fertile valleys, at immense dis- 

 tances from one another, it exhibits an almost con- 

 tinued scene of desolation and barrenness beyond 

 all description. The mean temperature may be 

 called 74°, and the diseases which sojourners have 

 chiefly to fear are intermittent and continued ar- 

 dent fevers, affections of the liver, cholera morbus, 

 and dysentery. I have entered at length, at an- 

 other place, into the discussion of these subjects, 

 and shall merely observe here, that by livingTtem- 

 perately, by avoiding exposure to the night air, or 



sleeping on the ground, and by attending to the 

 digestive functions, one may contrive to live com- 

 fortably, and preserve tolerable health, in most 

 parts of Peru. On this part of the coast we had 

 but little sickness in the Conway ; but some of the 

 vessels trading along-shore suffered severely from 

 intermittents, particularly at Arica, and the Patriot 

 Army under San Martin lost nearly one-third of 

 their number when encamped at Huacho, by dy- 

 sentery and intermittent fever, and their conse- 

 quences. Most of the diseases of Lima have their 

 immediate origin in affections of the stomach, so 

 that there is no disease which they do not refer to 

 Empachos, or indigestions, literally surfeits ; and 

 these, and all their other complaints, they ultimate- 

 ly refer to the effects of cold. Indeed, between 

 the tropics, the irritability of the human frame is 

 so much increased by the uniformity and continued 

 action of habitual stimulus, that it becomes sensi- 

 ble to alterations not indicated by the thermometer, 

 and depending solely on the humidity and dryness 

 of the atmosphere. 



The third division, extending a distance of nearly 

 1 700 miles from Payta to the entrance of the Gulf 

 of California, forms a perfect contrast with the second. 

 All this humid and burning coast has alternate 

 wet and dry seasons, and is clothed in the most 

 luxuriant vegetation, which approaches to the 

 water's edge. The mean temperature may be 

 called 82°. Mangroves, avicennias, and other 

 shrubs, flourish abundantly along these swampy 

 shores ; and their intertwining roots form retreats 

 for molluscse, and an infinite variety of shell-fish 

 and insects. Places of this kind are invariably 

 deleterious to the human constitution. The heat 

 and humidity of the air increase the development 

 of diseases in two different manners — by increasing 

 the irritability of the organs, and by the production 

 of miasmata. 



The disease which we chiefly encountered in this 

 tract was an ardent fever, resembling in every re- 

 spect the yellow-fever of the West Indies, both in 

 the suddenness of its attack, and the violence of its 

 symptoms. It yielded to precisely the same treat- 

 ment, by copious and properly regulated bleeding, 

 and purgatives — remedies which, in every case, 

 proved successful. 



