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466 PHILOSOPHICAL TRANSACTIONS, [aNNO 1 700. 



elude, that the coagulated blood in any animal, occasioned by a blow or bruise, 

 c:in in a few days be made to move again, it being taken for granted, that the 

 heart of a man pushes out the blood about 75 times in a minute. 



Now finding that in 14 days time the coagulated blood seems to vanish, and 

 also considering that in this time the heart performs its pulsation 1080000 

 times, and that in each motion, into several vessels together, only the size 

 of a grain of sand lias been loosened and set a going, how much may be set 

 a going in the time before-mentioned? Mr. L. could see, in the before- 

 mentioned blood vessel, each impulse which the blood received from the 

 heart. 



Now if we conceive that the size of a cubic inch of coagulated blood is very 

 much that is occasioned by a blow, and that seldom so much is coagulated at 

 once, then we may easily comprehend that such coagulated blood, by so many 

 motions as before-mentioned, may be loosened, and its motion restored again, if 

 not in all, yet in most of the vessels. 



At another time Mr. L. laid one of these tadpoles on a clean paper, for a little 

 while before he came to look upon it, by which a small part of the tail came to 

 be wounded, the skin being dry, and stuck to the paper, so that out of an artery 

 in that part, which seemed to be so large, that 4 red globules of the blood could 

 pass through it at once, some blood flowed out : yet that whereon his sight was 

 fixed, not being half a hair's breadth from the wounded part, there proceeded a 

 small branch of a vein, in which the circulation or flowing of the blood still re- 

 mained, as if the artery had not been broken. 



In fig. 1 1, TV represents the artery, wounded a little above v ; vx shows the 

 extravasated blood, vw the small artery, where the blood retained its full course, 

 although it was so near the vein as tv, whence the blood flowed, and was ex- 

 travasated. This seemed very strange at first ; but on observing that the blood- 

 vessel vw was united at w to a large blood-vessel that conveyed the blood to the 

 heart, then this blood out of vw was carried on with so great swiftness, as if im- 

 pelled from T to V ; nay, in such a manner, that he imagined that if the vein at v 

 was not united with t, but had only lain with its opening at v in the extravasated 

 blood, that so the extravasated blood was only for a little while sucked up and 

 conveyed through it. 



Then Mr. L. saw a vein, where the motion of the blood seemed very un- 

 common ; for example: let ab, fig. 12, be an artery in which the blood is 

 impelled with great swiftness from a to b; then we must call be, by which 

 the blood is conveyed towards the heart a vein : but what name must we give 

 to be, since, close by it tiicre lay another artery, viz. dee, througii which 

 the blood was also conveyed from the heart, from d to c. Now if the vein 



