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mined without the help of glalTes the circulation feems to be flow; 

 I have, in my mind, divided a minute of an hour into fevcnty- 

 two parts (inftead of fixly feconds, as is the common way of di- 

 viding time), and I reckoned each of thefe feventy-two parts or 

 portions of a minute, to be of fuch a length, that in it a perfon can 

 dillindly pronounce a word of four fyllables. 



I then took an eel, about a foot long, and placed it before the 

 microfcope, and, from the mod corred obfervation which I could 

 make, I judged that, in the feventy-fecond part of a minute, the 

 blood in one of the arteries, which was of a fize to admit three 

 or four globules of blood at a time to pafs through it, had pro- 

 ceeded the fpace of a fifteenth part of an inch; therefore the blood, 

 in one minute's time, palled over a fpace of four inches and four- 

 fifths of an inch; and this number being multiplied by fixty mi- 

 nutes, it follows that the blood in this eel could be carried or driven 

 forward 288 inches in the fpace of an hour. 



Now, let us fuppofe that the heart (which in eels is placed near 

 the head) was in this eel diflant from the end of the tail, where the 

 farthefl extent of the circulation is performed, 1 1 inches, it follows 

 that the blood, in its circulation, mufl be carried twice this dif- 

 tance, being 22 inches, before it returned back to the heart ; and 

 dividing the before mentioned number, 288 by 22, wefliall find that 

 in this eel the blood circulated to the extremity of the tail and back 

 to the heart, fomething more than thirteen times in the fpace of an 

 hour. 



In the next place, we will fuppofe that the ends of the blood-vef- 

 fels in the head, and in the fins next to the head, were in this eel 

 one inch and an half diflant from the heart, and, confequently, that 

 in thefe veflels the blood only performed a circuit of three inches; 

 it will follow, by the fame mode of computation as before, that in 

 thefe parts the blood might perform its circulation ninety-fix times 

 in the fpace of an hour. 



