99 



Any of the larger veins being tied with a thread, 

 swells between the extremes and the bandage, but 

 grows flaccid between the bandage and the heart ; if 

 opened in the former part it bleeds largely, if in the 

 latter scarce at rH. The blood therefore flows from 

 all the extreme*. thru.. 'M veins into the heart. ?jiu 

 still fi\. , ' ^ _ii^ .. * narts> c uJ vc* io the larger, 

 from the branches to the trunk. 



Upon the whole, it is evident that all the arteries 

 are continually bringing the blood from the left ven- 

 tricle of the heart, through the trunks of the arteries 

 into their branches, and from thence to all parts of the 

 body : and on the contrary, that ail the veins (except 

 the vena ports) are continually bringing it back from 

 all parts of the body, through the small branches into 

 the larger, and thence through the trunks and vena 

 cava into the right ventricle of the heart ; so that the 

 \vhole blood passes through the heart once in five or six: 

 minutes. 



It is certain that all the arteries and veins communi- 

 cate or open one into the other, because often from 

 one, and that a small artery, all the blood shall run 

 even unto death, not only out of the wounded limb, 

 but from the whole body. Of such fatal examples we 

 have a number ; from an inward artery of the nose, 

 from the gums, a finger, a tooth, a cutaneous pore en- 

 larged, from the lachrymal point, from the wound of 

 cupping on the skin, and even the bite of a leach. 

 There are, therefore, of course, open ways by which 

 the blood speedily tlows from the venal into the ar- 

 terial system, and the reverse. 



Late writers have pursued the globules of blood to a 

 great length, and found several orders of them. The 

 large ones visible to the naked eye are globules of the 

 first order. Each of these is composed of six smaller^ 

 joined together in a very regular way, but sometimes 

 a red globule is seen loosening and breaking into these 

 compounding spherules, and sometimes one may per. 

 ceive these running together and beginning the compos 

 sition of a new red globule. These smaller spherules 



