16 MOSQUITOES OF NORTH AMERICA 
above all at Mompox, at Chilloa, and at Tamalaméque. It is here that it is the 
largest and strongest, and here its legs are blacker. One can hardly help laugh- 
ing when one hears the missionaries dispute about the size and ferocity of the 
mosquitos on different parts of the same river. In the midst of a country where 
they are ignorant of what is going on in the rest of the world this is the favorite 
subject for conversation. ‘How sorry I am for you!’ the missionary of the 
Raudales on our departure said to the missionary of the Cassiquiare. ‘ You are 
alone just as I am in this country of tigers and of apes; fishes where I live are 
rarer than here; the heat there is greater, but as to the flies, I can boast that with 
one of mine I can beat three of yours.’ : : 
“ This voracity of insects in certain places, this avidity with which they attack 
man,* this activity of the venom, variable in the same species, are remarkable 
facts, but they find their analogy with some of the larger animals. The croco- 
dile of Angostura pursues man, while one can bathe peacefully at Nueva Barce- 
lona in the Nevari River in the midst of these carnivorous reptiles. The jaguars 
of Maturin, of Cumanacoa, and of the Isthmus of Panama are cowardly com- 
pared with those of the upper Orinoco. The indians know very well that the 
monkeys of such and such a valley are easily domesticated, while others of the 
same species, caught elsewhere, will die of hunger rather than submit to slavery. 
“The people in America form ideas concerning the health of climates and 
concerning pathological phenomena, just as the savants of Europe do, and these 
ideas, just as with us, are diametrically opposed to one another according to 
the provinces into which the new continent is divided. On the Rio de la Magda- 
lena the abundance of mosquitos is regarded as a nuisance, but very healthy. 
‘These animals,’ say the inhabitants, ‘ bleed us slightly, and in an excessively 
warm country, preserve us from the tabardillo, from scarlet fever, and other in- 
flammatory maladies.” On the Orinoco, the banks of which are very dangerous 
to health, the sick people accuse the mosquitos of all the diseases that they have. 
‘ These insects are born in corruption and increase it; they inflame the blood.’ 
It is useless to deny this poe belief which considers mosquitos as acting in 
a salutary way by local bleeding. Even in Europe the inhabitants of swampy 
countries do not ignore the fact that insects irritate the dermal system. Far 
from diminishing the inflammatory condition of the skin, the bites increase it. 
“The abundance of gnats and mosquitos characterizes unhealthy countries 
only when the development and multiplication of these insects depends upon 
the same causes which give birth to miasmas. These injurious animals love a 
fertile soil covered with vegetation, with stagnant pools, and moist air which is 
never agitated by the wind. They prefer, in place of bare spots, shade, that 
degree of light, of heat, and of humidity, which all favor the action of chemical 
affinities and accelerate the putrefaction of organic substances. Do the mos- 
quitos themselves add to the unhealthiness of the atmosphere? When one 
thinks that, at an elevation of three or four fathoms, a cubic foot of air is often 
peopled by a million winged insects and that these have within them a caustic 
and poisonous liquid—when one remembers that several species of Culex are 
from the head to the end of the body (without counting the legs) 1-4/5 lines 
long—when one considers finally that in this swarm of gnats and mosquitoes, 
spread like a cloud in the air, there are a great number of dead insects carried by 
the force of the ascending current and by the side currents which are caused by 
the unequal heat of the soil—one asks if the presence of so much animal matter 
in the air does not give birth to certain miasmas. I think that these substances 
* “ How surprising is this voracity, this appetite for blood on the part of littl h 
teed Donnas ge ae ge Pacturs five Yn oe pimost ‘uninhabited country ! ‘ what baa 
ou; ere,’ the creo 
there are only crocodiles covered with scaly skin and hairy cionkeyin im: paralng ‘planes: waere 
