( 102 ) 



in the rmallefl; arteries, fome of its parts are drawn off for thefupport 

 and nourirhmcnt of the body, wliereby the blood, when returning 

 in the veins, being deprived of thofc thin juices, aifun^es a darker red, 

 and as more of the thin juices are taken away, it will appear blackifn. 

 Tlie circulation of the blood is reprelbntcd in another view, at 

 fg. 8, A B C D E F G H I K, which is a drawing of fome veflbls feen 

 by the microfcope, in the tail of a tadpole ; thefe animals are much 

 quieter than eels, and the arteries and veins are as eafily to be feen 

 in them as in any other creature ; and in the fmalleft veilels where 

 the period, or the retrograde motion of the blood is performed, its 

 particles are more diftant from each other than in any other aniinal. 



The veilel, fliewn in this iigure, (which was an artery, wherein 

 the blood was driven fors\ard with great fwiftnefs from A to B) was 

 rather larger tlian to admit one of the particles of blood at a time. 

 At B it divided itfelf into two branches, which are re])refented at B C 

 and BE; thefe two branches were at D again united in one, for 

 a fhort fpace, and at F they again feparatcd, as fliewn at F G and 

 F I. Here thefe two arterial branches, making a fmall curve, or 

 bend, again joined in one at H, forming a fomewhat larger vefliel, 

 which is feen at H K , and at K, this was joined to a (till larger 

 blood-velTel. 



Here it is plain, that the veflels A B C t) E FG, and ABEFI, 

 forafmuch as in them the blood is driven from the heart, to G and 

 I, its greateft dillance, muft be named arteries ; and the veflels G H K 

 and I H K, becaufe in them the blood is returning to the heart, 

 muft be named veins. 



I formerly was of opinion, that in all cafes where by an accidental 

 fall or blow, there were produced livid or purple fpots upon the 

 Ikin, which proceeded from coagulated blood, this blood (if no 

 exulceration fliould take place in the part) would by degrees be lb 

 diflolved, as to be carried off by perfpiration ; but the following 

 fervations caufed me to alter my opinion in this relpebl. 



