PHODUCED BT THE MOSQUITOS. 
285 
li^ht, heat, and moisture which, while it favours the action 
of chemical affinities, accelerates the putrefaction of organ- 
ised substances. May not the mosquitos themselves in- 
crease the insalubrity of the atmosphere P When we reflect, 
that to the height of three or four toises a cubic foot of air 
is often peopled by a million of winged insects,* which 
contain a caustic and venomous liquid ; when we recollect 
that several species of culcx are 1‘8 line long from the head 
to the extremity of the corslet (without reckoning the legs); 
lastly, when we consider that in this swarm of mosquitos 
and gnats, diffused in the atmosphere like smoke, there is 
a great number of dead insects raised by the force of the 
ascending air, or by that of the lateral currents which are 
caused by the unequal heating of the soil, we are led to 
inquire whether the presence of so many animal substances 
in the air must not occasion particular miasmata. 1 think 
that these substances act on the atmosphere differently from 
-and and dust; but it will be prudent to affirm nothing 
positively on this subject. Chemistry has not yet unveiled 
the numerous mysteries of the insalubrity of the air; it has 
only taught us that we are ignorant ot many things with 
"Inch a few years ago we believed we were acquainted. 
Daily experience appears in a certain degree to prove the 
fact that at the Orinoco, Cassiquiare, Bio Caura, and where- 
ver the air is very unhealthy, the sting of tbe mosquito 
augments the disposition of the organs to receive the im- 
pression of miasmata. When you are exposed day and 
night, during whole months, to the torment of insects, the 
Continual irritation of the skin causes febrile commotions ; 
and, from the sympathy existing between the dermoid and 
file gastric systems, injures the functions of tbe stomach, 
‘digest ion first becomes difficult, the cutaneous inflamma- 
tion excites profuse perspirations, an unquenchable thirst 
su seeds, and, in persons of a feeble constitution, increasing 
'"'patience is succeeded by depression of mind, during 
"fiich all the pathogenic causes act with increased violence, 
ft is neither the dangers of navigating in small boats, the 
savage Indians, nor the serpents, crocodiles, or jaguars, that 
uiake Spaniards dread a voyage on the Orinoco ; it is, as 
. It is sufficient to mention, that the cuoic foot contains 2,985,98 i cubic 
'•nes. 
