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fabric, as to conceive and explain its me- 
chanifm. The quantity of blood which 
palfes through it is enormous. It has 
been eftimated at one third, and in the 
more moderate calculations, at one fourth 
part of the whole mafs. This blood after 
having circulated through it, and after¬ 
wards defcended by the jugular veins to 
the heart, is fent back again feveral times 
to the brain. The artifice, which nature 
has employed for this purpofe, is amonglt 
the moft Angular we have any knowledge 
of. 
We fihall take fome notice of it in this 
place, both becaufe it is not fufficiently 
known, and becaufe it leads us to a re- 
fearch which is nearly connected with our 
fubjedl. 
We are indebted to M. Cotunnio for 
this beautiful difcovery, and he owes it to 
accident. Being engaged in fome enqui¬ 
ries concerning the organs of the voice, 
he 
