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natural history. 
But it is not in this instance alone that the leech differs 
from all other insects. It was remarked in a former section, 
that the whole insect tribe had the opening into their lungs 
placed in their sides ; and that they breathed through those 
apertures as other animals through the mouth. A drop of oil 
poured on thesides of a Wasp, a bee, or a worm, wouldqutckly 
suffocate them, by stopping up the passages through which 
they breathe ; but it is otherwise with the leech, for this ani- 
mal may be immersed in oil without injury ; nay it will live 
therein ; and the only damage it will sustain is, that when 
taken out it will be seen to cast a fine pellucid skin, exactly 
of the shape of the animal, after which it is as alert and vigor- 
ous as before. It appears from this, that the leech bieathes 
through the mouth ; and, in fact, it has a motion that seems 
to resemble the act of respiration in more perfect animals ; 
but concerning all this we are very much in the dark. 
This leech is viviparous, and produces its young one after 
the other, to the number of forty or fifty at a birth. It is 
probable that, like the snail, each insect contains the two 
sexes, and that it impregnates, and is impregnated in the same 
manner. The young ones are chiefly iound in the month oi 
July, in shallow running waters, and particularly where they 
are tepified by the rays of the sun. The large ones are chief- 
ly sou "hi after; and being put into a glass vessel filled with 
water, "they remain for months, nay for years, without taking 
any other subsistence. But they never breed in this con- 
finement ; and consequently, what regards that part of then 
history still remains obscure. 
In this part of the world they seldom grow to above four 
inches ; but in America and the East they are found from 
six to seven. Their pools there abound with them in such 
numbers, that it would be dangerous bathing there, if from 
no other consideration. Our sailors and soldiers, who the 
last war were obliged to walk in those countries through 
marshy o-voiinds, talk with terror of the number of leeches 
that infested them on their march. Even in some parts of 
Europe they increase so as to become formidable. Scde- 
1 i ns, a (Herman physician, relates that a girl of nine years 
old, who was keeping sheep near the city of Bornst, m 
Poland, perceiving a soldier making up to her, went to 
hide herself in a neighbouring marsh, among some bushes; 
but the number of leeches was so great in that place, 
and they stuck to her so close, that the poor creatin' 3 
expired from the quantity of blood which she lost by 
their united efforts. Nor is this much to be wondered ilt > 
since one of these insects, that, when empty, generally 
