( 101 ) 



A little higher in the artery D, a Imall artery branches off at /, pro- 

 ceeding to k and /, where it again divides itfelf into two, and joins 

 the vein E at m and 7i. 



Clofe to /, two Imall branches arife at o, and join the vein C at 

 p and q. 



At /■ arifes another fmall artery r s, which at s divides into two 

 mailer branches, one of them taking the courfe s t, to join the vein 

 C, and the other paffing by s u zv x, to join the vein E. 



Lallly, the extremity, or Imallefl part of the artery D, is fliewn 

 at ry z, and is united to the vein E at A, firft fending oii^' a branch 

 jiear the letter ?<, which taking the direction u b, is united to the 

 vein C at t. 



Hence it plainly appears, how many various branches or minute 

 arteries proceed from thofe fmall blood-veflels, or arteries, repre- 

 iented at B; D and F, and how thefe all unite wuth the other fmall 

 veflels called veins, which are (liewn at A, C and E ; and this alfo 

 proves what has been fo often mentioned, that all thefe blood-veliels, 

 tiiough called by ditierent names, are yet the fame identical velfels. 

 And if we reflect, that each of thefe very fmall veflels mufl: be 

 formed with the fame kind of coat as the larger ones though of a 

 thinnefs proportioned to its fize ; and farther, if we confider of 

 wliat wonderfully fine and invifible membranes the coats of the 

 fmalleft veffels mufi: be formed, and how eafily the finefl: part of the 

 arterial blood may find a paflage through thofe coats, to the end that 

 every part of the body may, from thence, be continually fupplied 

 with necelTary and fuitable nourifliment ; thefe things, I fay, be- 

 ing duly weighed and confidered, it feems clear that tlie arterial 

 blood, coming from the heart, mud contain more fubtile and fluid 

 parts than when in its paflage to the heart. For the blood will not 

 be deprived of its more fubtile juices, while in the larger arteries; 

 to prevent which, I imagine that they are provided with thick and 

 folid coats. And here the particles of blood from which its rednefs 

 proceeds, fwimming in a thin juice, are of a bright red colour; but 



