110 



insects are born of corruption, and increase it ; 

 they vitiate and inflame the blood (viciany enci- 

 enden la sangre)." It would be useless here to 

 refute the popular belief, that considers the ac- 

 tion of the moschettoes as salutary by it's local 

 bleedings. Even in Europe the inhabitants of 

 marshy countries are not ignorant, that the in- 

 sects irritate the dermoid system, and stimulate 

 it's functions by the venom, which they deposit 

 in the wounds they make. Far from diminish- 

 ing the inflammatory state of the integuments, 

 the stings increase it. 



The frequency of gnats and moschettoes cha- 

 racterizes unhealthy climates only so far as the 

 development and multiplication of these insects 

 depend on the same causes, that give rise to mi- 

 asmata. These noxious animals love a fertile 

 soil covered with plants, stagnant waters, and a 

 humid air never agitated by the wind ; they pre- 

 fer to an open country those shades, that soften- 

 ed day, that tempered degree of light, caloric, 

 and humidity, which, while it favors the action 

 of chemical affinities, accelerates the putrefaction 

 of organized substances. Do the moschettoes 

 themselves increase the insalubrity of the at- 

 mosphere ? 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 



* It is sufficient to mention on this occasion, that the cubic 

 foot contains 2,985,984 cubic lines. 



