VOL. XXII.] PHILOSOPHICAL TRANSACTIONS. 465 



that about 20 of these red globules could run together at once through it. 

 This was a great artery, in comparison to those abovementioiied, and in this 

 the blood moved very slowly, a small portion of which is delineated in fig. ]0, 

 at LM. Out of this blood vessel proceeded a less one, as mo. The blood in 

 the vessel from l to m, had not so quick a motion as it had in other?, because 

 the blood in the vessel at k stagnated in a manner, so that no separated parts 

 could be discerned in the blood, for it appeared there of one uniform red 

 colour. Yet in the blood vessel mo the circulation was as swift as in any 

 other vessel. Mr. L. was fully persuaded that the blue spots, occasioned by 

 a fall or a bruise, were not stagnated blood that was stopped, and that this 

 coagulated blood, which before it begins to corrupt, perspires through the skin 

 with the sweat, by the following observation. The blood by r being thus with- 

 out the least motion, it was by every pulsation of the heart impelled upwards 

 from N to p, and the next moment it recoiled back again, and so backwards and 

 forwards with an undulatory motion. As is known, if we use ever so great vio- 

 lence in the compression of water, yet we cannot press it closer together than it 

 was before ; so the blood being now impelled forwards through the heart, cannot 

 be compressed into a less place. 



This being so, we must conclude, that the tunic of the blood vessel between 

 N and p, and also somewhat below n, is distended by every pulsation of the 

 heart; and as soon as this uncommon distension is performed, so soon also does 

 the tunic of the vessel contract again, by which the blood that was thus pushed 

 forth is driven and forced to run back again. 



Mr. L. after some time, observed the blood began to move, from p to r, 

 after such a manner, as to be pushed back again ; and he judged that the blood 

 vessel MO was during his observation a little more distended, and of course 

 more blood ran through it than when he first began to look on it. The blood 

 in the vessel ns, wherein before was little or no motion, now ran as swift as 

 in any other vessel. The blood vessel pa, which was so small, that but one 

 single particle of the blood could pass through it at once, and wherein at first 

 view there was not the least motion to be discerned, now also began to flow; 

 yet the particles of the blood that at first passed through it, were but few in num- 

 ber, and consequently far asunder. Further, all the blood from p to r WdS put 

 into a motion, as well by being put forward, as by running back again, and that 

 at every pulsation of the heart. 



So that now it plainly appears, that the stagnant blood cannot only be made 

 to move again by the motion of the heart, which we call the beating uf the 

 pulse, but also, that the coagulated red globules of the blood are dissolvi d 

 again, and assume their first figure. And therefore there is reason to con- 



VOL. IV. 3 O 



