170 
CLIMATE. 
healthy, and rheumatism and catarrhs are the only diseases of 
note ; sometimes fever and ague in October. There, the rainy 
season commences in June (latter part), and extends through 
July, August, September, and October. The average age of 
the oldest inhabitants is sixty years. 
On the northeastern division of the Isthmus, bordering the 
Gulf, where the rainy season begins in the middle of June and 
terminates in November, the district appears to be unusually 
healthy, and it is not uncommon to meet with natives seventy 
and eighty years of age residing there. 
The less healthy portion is, without doubt, the Coatzacoalcos 
Eiver, along the mouth and delta of which, fever, ague, and re- 
mittent fever of a bilious type are prevalent during July, 
August, and September. The people who inhabit this region 
are miserably poor, and the insects numerous and annoying. 
There is no doubt that in alluvial plains, which are generally 
level and well watered, the slow current of the streams and the 
luxuriant vegetation give rise, by the decay of vegetable mat- 
ter, to the development of miasmata and gaseous matters, which 
produce fevers of an intermittent and typhoid character. Man- 
kind are not necessarily victims to these diseases, unless by 
absence of precaution, or a lowered state of health, the constitu- 
tion becomes impaired, so that it is unable to resist the miasma. 
Cleanliness of skin, temperance in eating and drinking, and 
clothing to defend against alternations of temperature, are sure 
preventives against the influences of a moist climate and a 
damp soil — influences which are equally hurtful, whether in 
New England or on the plains of Mexico. 
There is no reason to doubt that when the northern slope 
becomes more inhabited, and the forest cleared somewhat, so 
that the sun's rays may reach and dry the ground, much of its 
present injurious effect on the constitution will disappear : the 
demand for forest timber and the cutting down of trees for 
medicinal and commercial purposes will also remove the 
humidity and drain the soil remarkably. The use of flannel 
next the skin should never be omitted by inhabitants of the 
whole northern slope, and a small fire should be kept in the 
rooms during the rainy season when the thermometer sinks low. 
