120 YELLOW FEVER. 



of the year in these several districts is as follows : 

 At La Guayra, nearly 82*6 ; at Cumana, 81.2; at 

 Vera Cruz, 77'7 ; at Havana, 78'1; while at Rio 

 Janeiro it is 74'5 ; at Santa Cruz in Teneriffe, 71'4 ; 

 at Cairo, 72.3 ; and at Rome, 60'4. 



At the time of Humboldt's visit to La Guayra, 

 the yellow fever, or calentura amarilla, had been 

 known only two years there, and the mortality had 

 not been very great, as the confluence of strangers 

 was less than at Havana and Vera Cruz. Some 

 individuals, even Creoles and mulattoes, were occa- 

 sionally taken off by remittent attacks, complicated 

 with bilious symptoms and hemorrhages, and their 

 death often alarmed unseasoned Europeans ; but the 

 disease was not propagated. On the coast of Terra 

 Firma this malignant typhus was known only at 

 Porto Cabello, Carthagena, and Santa Martha. But 

 since 1797 things have changed. The extension of 

 commerce having caused an influx of Europeans and 

 seamen from the United States, the distemper in 

 question soon appeared. It is maintained by some, 

 that it was introduced by a brig from Philadelphia, 

 while others think it took its birth in the country 

 itself, and attribute its origin to a change in the 

 constitution of the atmosphere caused by the over- 

 flowings of the Rio de la Guayra, which inundated 

 the town. This fever has since continued its rav- 

 ages, and has proved fatal, not only to troops newly 

 arrived from Spain, but also to those raised far from 

 the coast, in the Llanos between Calabozo and Uri- 

 tuco, a region nearly as hot as La Guayra itself. It 

 scarcely ever passes beyond the ridge of mountains 

 that separates this province from the valley of Ca- 

 raccas, which has long been exempted from it. The 

 following are the principal pathological facts having 

 reference to this frightful pestilence : 



When a great number of persons, born in a cold 

 climate, arrive at a port in the torrid zone, the insa- 

 lubrity of which has not been particularly dreaded 



