CHAP T HR 1 
HIRUDO—THE LEECH. 
Awone the numerous tribes of the lower animals distributed through- 
out the universe, none has attracted equal notice perhaps as the Leech, 
and that from periods of the most remote antiquity. Its form, its mo- 
tions, its habits, are well adapted to excite the curiosity of the illiterate 
beholder, and, above all, its utility in alleviating the afflictions of man- 
kind, have gained a distinction for it which is denied to all the rest. 
Though widely known of old, in general, the detailed investigation 
of the history of the Leech has been reserved for the latest era of scienti- 
fic observers, and the most advanced state of science. 
Doubtless the noted peculiarities of the Medicinal Leech led to the 
study of others, whether from motives of mere curiosity, or from the 
hopes of finding them endowed with similar properties. Such expecta- 
tions however have been disappointed ; for among a genus, abounding suf- 
ficiently in the variety of its species, I believe that no one is yet discovered 
which can be so satisfactorily employed in relieving human distress. 
It is true that in this country there are leeches that will suck the 
blood, and eat the flesh of animals; and that in some distant regions 
others prove a kind of pest to man, but none seem as yet habituated to 
the same office wherein the Medicinal Leech is so useful at home. 
Independently of the practical value of this animal, wherever it can 
be found, certain singular facts are exposed by various species of the 
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