IMPROVED, 59 



feparated from any Part, and taken out of the Body ; 

 which plainly appears upon any Solutio Continuiy or 

 dividing of the Parts by a Wound, ^c. ; I mean 

 where fuch Divilion is tranfverfe or a-crofs. But 

 this Explanation might, perhaps, feem a little too 

 prolix for my intended Brevity : I fliall therefore 

 conclude with faying, that when the Arteries, 

 which (as I have fhewn) are a Compofition of 

 Fibres, are raifed by the Impulfe of the Blood from 

 the Heart, to a certain Meafure or Pitch, wherein 

 their Endeavours of Reftitution will exceed the 

 Impulfe that raifed or diflradled them, their Con- 

 tra(rtile Powers will draw them again into the 

 fame Dimenfions they were in before fuch Impulfe, 

 and confequently the Blood will be thruft forward 

 into the next Section of the Artery, and fo on fuc- 

 ceiTively from one to another through the whole 

 Courfe of it*s Circulation j the Contraction of one 

 Se£lion of an Artery being the true Caufe of the 

 Blood's Impulfe againft, and raifmg the next. 



The moll natural Confequence of this Motion 

 will be breaking ftill fmaller the Parts of that 

 Fluid, which is difpenfed to lubricate or facilitate 

 the Motion of the Fibres i which Comminution will 

 continue till it is rendered fo fine as to fly off at the 

 Surface whenever it happens to get there ; and that 

 which thus infenfibly flies off, is the true Materia 

 Per/pirabiiis oiSanSicrius, which that Authar has SahStorins'/ 

 fo learnedly treated upon. But, before it is {q MxeriaTtr- 

 broke, and ferves for the Purpofes aforementioned, ■^^'^'*^'j.''"> 

 it is that which is to be underftood by the common 

 Terms of Animal Spirits or Oil, Liquidufn Ner<vo- 

 funty Succus Ner^'ofus, the Nervous Fluid or Juice, 

 and the like ; and any Thing elfe, drnominated a 

 Spirit in a Human Body, { that is not fubjed to 

 Mechanical Laws ) belongs to another Order or Sec 

 of Men to explain ; but in my Thoughts, lies 

 quite out of the Reach of that Reafon w^hich a 

 Phyfician is compelled to take up for his fureil 

 Guide. And I hope to Ihew in the Sequel of this Trea- 



tife. 



