Chap. VL Of Fevers in general 2 s 



the BIood-veiRls, which moves with To much Rapidity ns 

 .to dilcompofe the whole Body. And in thofe Fevers that 

 proceed from vitiated Blood,' and are the Effects of fome 

 .other Dife?.fc, fhe is opnreiled by violent Impulfes and irre- 

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

 ture and iMake as to render it fit to pafs equally into all Parts„ 



And therefore it is to be obferved, that jiip^^,frsha'V2 

 whatever Changes the Biood under^^oes ni j-^^ ^;^-^ -^^^^^ 

 all the different Kinds of a Fever, fo long dtatsCaufe, ei- 

 as the Difeafe lafts, thefe Changes muil: Iiave ther a too great 

 a Tendency either to aD over- great Rarefac- Thidnefs or 

 tion or Thinnefs, or elfe to an over-great ninnefs of the 

 Thicknefs, or to an Inequality of the Sub- ^i'< ;; ^; 

 ft.nce of the Blood, whereby fome Parrs of f/XZlfe 

 it will pafs more eafilv than others through ^ 



the fmalleil Veilels ; all which may at one 

 Time or other produce the Symptoms common to all Fe- 

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

 the Arteries, b'f. This is fo clear and evident, m Cale oi: 

 an over-great Rarefadion and Thinnefs of the Biood, that 

 it needs no Manner of Proof, lince Heat muft always be 

 the EiFea of Motion. And, on th^ other fjancj, when 

 the Blood happens to be too much coagulated and tliick- 

 tn'd, and when it is render'd of too adhehve and gluey 

 a Nature, whatever be the Figure and Size of it^s Particles, 

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

 be obftruited in the fmalieft Paflages ; and thcie Obllruc- 

 tions in the fmalleil Pailages, mult give it a more than 

 ordinary Dc-ree of Motion in thofe V^efiels^ that are large 

 enough to receive it, and confequently its Heat mull alfo 

 be au2;mented. 



But^this will be the more eafily undcrilood, In n.vhat Man. 



if we confider that the Arteries, which carry ^er^^ the Biood 

 the Blooa into all Parts, grow gradually ^;;^l'^'^2e ' 

 fmalier the farther they advance trom the ^^^'^Jy^.l 



mer ivhen it i. 



Heart; and that there is a proportlonably 

 iefs Diftance betwixt their Branches, and towards their 

 Extremities, as the Diihnce between thefe capillary 

 Branches grows ftiil fmalier, rcfemblmg the little Fila- 

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

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

 Sum of all the Orifices of the fucceeding Branches of every 

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

 which muft be io great a Beneiit to K^liire, that unlets 



K 4 tho(b 



