390 
PERU 
CHAP. 
by the drainage of some little pools. Miasma is not always 
produced by a luxuriant vegetation with an ardent climate ; 
for many parts of Brazil, even where there are marshes and a 
rank vegetation, are much more healthy than this sterile coast 
of Peru. The densest forests in a temperate climate, as in 
Chiloe, do not seem in the slightest degree to affect the healthy 
condition of the atmosphere. 
The island of St. Jago, at the Cape de Verds, offers 
another strongly-marked instance of a country, which any one 
would have expected to find most healthy, being very much 
the contrary. I have described the bare and open plains as 
supporting, during a few weeks after the rainy season, a thin 
vegetation, which directly withers away and dries up : at this 
period the air appears to become quite poisonous ; both natives 
and foreigners often being affected with violent fevers. On 
the other hand, the Galapagos Archipelago, in the Pacific, with 
a similar soil, and periodically subject to the same process of 
vegetation, is perfectly healthy. Humboldt has observed that, 
“ under the torrid zone, the smallest marshes are the most 
dangerous, being surrounded, as at Vera Cruz and Carthagena, 
with an arid and sandy soil, which raises the temperature of 
the ambient air.” 1 On the coast of Peru, however, the 
temperature is not hot to any excessive degree ; and perhaps 
in consequence the intermittent fevers are not of the most 
malignant order. In all unhealthy countries the greatest risk 
is run by sleeping on shore. Is this owing to the state of the 
body during sleep, or to a greater abundance of miasma at 
such times ? It appears certain that those who stay on board 
a vessel, though anchored at only a short distance from the 
coast, generally suffer less than those actually on shore. On 
the other hand, I have heard of one remarkable case where a 
fever broke out among the crew of a man-of-war some hundred 
miles off the coast of Africa, and at the very same time that 
one of those fearful periods 2 of death commenced at Sierra 
Leone. 
No State in South America, since the declaration of 
1 Political Essay on the Kingdom of Neiv Spain, vol. iv. p. 199. 
2 A similar interesting case is recorded in the Madras Medical Quart . Journ. 
1839, P- 340. Dr. Ferguson, in his admirable Paper (see 9th vol. of Edinburgh 
Royal Trans.), shows clearly that the poison is generated in the drying process ; and 
hence that dry hot countries are often the most unhealthy. 
