24 The Farrier'j Kew Guide. Chap. VI. 



thofe Veflels had been of fuch a Texture, it would have 

 been impofTible for any animal Body to have been fup- 

 ported under the leafl Diforder. But notwithftanding this 

 wife Contrivance, the Blood is ftill very liable to Obltruc- 

 ;ion vi'henevcr it happens to be too thick or vifcid. And 

 as all fuch Obftrudtions muft rationally happen in thofq 

 Parts where the Vcilels are of the fmallelt Texture, that 

 wliich flows in thofe that are larger, mud of Confequcnce 

 move with greater Rapidity ; becaufe, as has been already 

 hinted, v/hen it meets with Oppolition in its Courfe for- 

 wards, it mull; deviate in greater than ordinary quantity, 

 and with greater Force, into the ncareft lateral Branches. 



Nature furniflies us with few Similitudes that would be 

 of any Service to illuflrate iljis fort of Mcchanifm, unlefs 

 a general Refemblance could be fu{hcient. Neither docs 

 Art aflift us othtrwife than by Mathematical Experiments, 

 which would not be eafily underflood but by thofe who 

 . ' _,^ ._ have fome infight into them. But that this 

 ''en tahJfrom "^''>' ^^ "^^^^^ as plain as poffibic, we fliall 

 Water runrirg fuppofe an Artery to be like a Pipe, which 

 in Pipes, &c. grows gradually fmallcr, according to the 

 number of Branches it fends forth. We 

 muft alfo fuppole this Pipe, and all its Branches, to be 

 conftantly filled with Water from f.^ime Fountain, and this 

 Water perpetually running frcm the mam Trunk into all 

 thefe Branches : We muft in like manner imagine the; Ex- 

 tremities or Endings of thofe Branches to be fo fmall, as 

 to be eiiiily choak'd up with Ssnd or Clay, or any other 

 I-cind of Matter ; and therefore when any fuch Matter 

 happens totally, or in Part, to oblhufl: one or more of 

 ;hcfe fmall Paflages, the Water meeting with Refinance is 

 forced back Jigain, and is taken up by thofe Branches that 

 are the nearclt i fo the Branches, which are antecedent to 

 thofe that are thus obilrufted, receive not only a more 

 than ordinary quantity of Water, but this Water is alfo 

 increafed in its motion in proportion to the Force by which 

 it is repulb'd; and likewile by that of the Water, which is 

 antecedent to i% which beiqg alfo in Motion, muft relift 

 jrs returning ihe fame way it came ; and, by giving a new 

 Impetus to the Water thus repulfcd, muft drive it with the 

 greater Force into the lateral Branches. And this will 

 .ippear ftill more manifeft from the Inftance of a large 

 Stone thrown into a very fmall Brpok or Rivulet, which 

 raking up feme Space, ijnd dividing ih? Stream in the 



niidulej 



