CLIMATE. 
during the night. The clear mountain springs furnish excellent 
water. There is an abundance and great variety of fruits, and 
the inhabitants, chiefly Zapotecos, are peaceably and quietly 
disposed. 
The last portion of the Isthmus to be described is that of 
the plain of Tehuantepec, which stretches from the southern 
side of the Cordillera to the coast of the Pacific Ocean. The 
moment you descend the mountains, you perceive that you are 0 
in an entirely different region. The sturdy oak, and the thick 
dark-green foliage of the trees in the hilly regions, are replaced 
here by large varieties of bluish-leaved mimosa, of cactus, and 
other vegetation peculiar to a tropical climate. The soil is gen- 
erally light and sandy, the rivers but few, rather small streams 
when compared with those of the northern part of the Isthmus. 
On this plain there are several large villages, inhabited by Za- 
poteco Indians. The city of Tehuantepec, the head of the depart- 
ment of that name, contains from twelve to fourteen thousand 
inhabitants. Although the mean temperature of this valley is 
higher than that of the plain of Coatzacoalcos, it enjoys a degree 
of salubrity not inferior to that of the region of the mountains. 
The season of the rains is shorter here than on the north side ; 
and the heat of the sun during the dry season-is mitigated by the 
north wind and the variable breezes in the wet season. I never 
heard of a single case of sun-stroke either among the natives or 
strangers. The air is pure and dry, and it never feels as oppressive 
as it often does in the summer-time at New Orleans. The natives 
complain chiefly of indigestion and some other derangements of 
the bowels, which are generally the consequences of all kinds of 
excesses ; besides, these diseases are more prevalent in tropical 
climates than in temperate and cold ones. In some parts of the 
plain, as near the upper and lower lakes, in the neighborhood of 
San Francisco and Boca-Barra, the intermittent fevers prevail, 
particularly after the rainy season is over ; but the yellow fever 
is unknown in this region, nor did I hear of any other epidem- 
ical pernicious fever. During our stay at Tehuantepec, while 
preparing for departure, I met with but few cases of sickness, 
and these were not of a character peculiar to the country, but 
such as would occur accidentally in all places. I saw and treated. 
