For example, let us fuppolc, that tlie quantity of blood, ^'(^ 



which at every puliation can be rendered fluid, and reftored 



to its motion, is no more than the fize or quantity of a grain ''"'^g,, 



of fand, and that eighty of fuch grains placed fide by fide do • " • 



111 I r • 1 !• 1 1 1 512000 



not exceed the length of one nicli ; we hnd then that 512000 . 



grains of fand taken together are equal to a cubic inch, which num- 

 ber is not the half of the number above affigned. 



In this blood-veffel, which I have jufi: mentioned, I could not only 

 very clearly difcern the feveral pulfations, but I could alfo many 

 times in all the arteries, fee to make an exa6l computation how 

 many times the blood was propelled from the heart in the fpace of one 

 minute. 



Now, if we confider that fo great a quantity of blood, as is con- 

 tained within the compafs of a cubic inch, is very rarely by a blow 

 or bruife congealed in one fpot, we may eafily conceive, that when a 

 coagulation does happen, it may, by fuch frequent propulfions or 

 pulfations as I have mentioned, be at length dillblved, and in all, or 

 mofi: of the vefllels, reflored to the fame current or courle as before. 



At another time, I obferved an appearance of a different nature 

 in the blood- vefTels, which was occafioned by my having put a tad- 

 pole into a piece of clean paper, whereby a fmall fpot in the very 

 thinnefi; part of its tail ftuck to the paper, and thereby received a 

 fmall injury, fo that fome blood flowed from the wound, out of an 

 artery which was of a fize to admit about four globules of blood to 

 pafs through it at a time. 



The blcod thus flowing out, remained collected about the wound- 

 ed part ; but here another fight prefented itfelf, wliich engaged all 

 my attention; for, in this fame artery, at about tlie half of an hair's 

 breadth diflancc from the wounded part, another fmall branch ap- 

 peared, wlierein the blood purfued its courfe in the fnne uniform and 

 diftin6l manner, as if the artery had remained uninjured. 



O 



