112 
CUIUODS SEAWEED. 
opinion is very general, although there are examples of per- 
sons, who, having escaped a first attack of the yellow fever, 
have fallen victims to the same disease in one of the follow- 
ing years. The facility of becoming acclimated, seems to be 
in the inverse ratio of the difference that exists between the 
mean temperature of the torrid zone, and that of the native 
country of the traveller, or colonist, who changes his cli- 
mate ; because the irritability of the organs, and their vital 
action, are powerfully modified by the influence of the atmo- 
spheric heat. A Prussian, a Pole, or a Swede, is more exposed 
on his arrival at the islands or on the continent, than a 
Spaniard, an Italian, or even an inhabitant of the South of 
Prance. "With respect to the people of the north, the dif- 
ference of the mean temperature is from nineteen to twenty- 
one degrees, while to the people of southern countries it is 
only from nine to ten. We were fortunate enough to pass 
safely through the interval during which a European re- 
cently landed runs the greatest danger, in the extremely 
hot, but very dry climate of Cumana, a city celebrated for its 
salubrity. 
On the morning of the 15th, when nearly on a lin e with the 
hill of St. Joseph, we were surrounded by a great quantity 
of floating seaweed. Its stems had those extraordinary 
appendages in the form of little cups and feathers, which 
Don Hippolyto Kuiz remarked on his return from the expe- 
dition to Clnle, and which he described in a separate memoir 
as the generative organs of the Fucus natans. A fortunate 
accident allowed us the means of verifying a fact which had 
been but once observed by naturalists. The bundles of fucus 
collected by M. Bonpland were completely identical with the 
specimens given us by the learned authors of the Flora of 
Peru, On examining both with the microscope, we found that 
the supposed parts of fructification, the stamina and pistils, 
belong to a new genus, of the family of the Ceratophytse. 
The coast of Paria stretches to the west, forming a wall of 
rocks of no great height, with rounded tops and a waving 
outline.. We were long without perceiving the hold coasts 
of the island of Margareta, where we were to stop for the 
purpose of ascertaining whether we could touch at Gruayra. 
We had learned, by altitudes of the sun, taken under very 
favourable circumstances, bow incorrect at that period were 
