Chap. VI. Of Fevers in general.' 25 



the Blood- vefl'cls, which moves with fo much Rapidity as 

 to difcompofe the whole Body. And in thofe Fevers that 

 proceed from vitiated Blood, and are the Effects of fome 

 other Difeafe, (he is opprefled by violent Impulles and irre- 

 gular Difcharges before the Blood can become of fuch a Tex- 

 ture and Make as to render it fit to pafs equally into all Parts. 



And therefore it is to be obferved, that ^,/p , 

 1 «-,! 1 T)i J J • All Fevert have 



whatever Changes the Blood undergoes in j-^^ ^/,^^y mme- 



all the different Kinds cf a Fever, fo long diateCaufe, ei- 

 as the Difeafe lafts, thefe Changes muft have ther a t^o great 

 a Tendency either to an over-great Rarefac- Thicknejs or 

 lion or Thinnefs, or elfe to an over-great T^hinnifs of the 

 Thicknefs, or to an Inequality of the Sub- Blood, or an 

 fiance of the Blood, whereby fome Parts of ^''"i''fp "f ■ 

 it will pafs more eafily than others through ''' ^'it>M»ce. 

 the fmalleft Vellels ; all which may at one 

 Time or other produce the Symptoms common to all Fe- 

 vers, to wit, a violent and exxeliive Heat, and beating of 

 the Arteries, ilfc. This is fo clear and evident, in Cale of 

 an over-great Rarefaction and Thinnefs of the Blood, that 

 it needs no Manr;er of Proof, iince Heat muft always be 

 the Effect of Motion. And, on the other Hand, when 

 the Blood happens to be too much coagulated and thick- 

 en'd, and when it is render'd of too adhelive and gluey 

 a Nature, whatever be the Figure and Size of its Particles, 

 or whatever other Qualities may be in it, it muft certainly 

 be obftructed in the fmalleil Paflages ; and thefe Obllruc- 

 tions in the fmalleft Paflages, muft give it a more than 

 ordinary Degree of Motion in thofe Vellels that are large 

 enough to receive it, and confequently its Heat muft alio 

 be augmented. 



But this will be the more eafily underftood, In <what Man. 

 if we confider that the Arterie?, which carry "er the Blood 

 the Blood into all Parts, grow gradually i-jUI caufe a Fe- 

 fmaller the farther they advance from the YtTick" " " 

 Heart ; and that there is a proportionably ^''^ * '^ " 

 lefs Diftance betwixt their Branches, and towards their 

 Extremities, as the Diftance between thefe capillary 

 Branches grows ftill fmaller, refembling the little Fila- ■ 

 ments on the Leaves of Trees. It is alfo to be taken 

 Notice of, that, according to the lateft Difcoveries, the 

 Sum of all the Orifices of the fucceeding Branches of every 

 Artery, is larger than the Trunk from whence they arife, 

 which muft be fo ^reat a Benefit to Nature, that unlcfs 



K 4 ihgfe 



