22 The^ARKJ^K's New Guide. Chap. VI. 



But firft, it will be proper to diflinguifh between a Fever 

 that is Simple, and that which is complicated and accom- 

 panied with fome other Diicafe. A fimple Fever confifts 

 only in the Increafe of the Blood's Velocity ; that is to fay, 

 ■when it runs more fwiftly through all its Channels than is; 

 ufual, but preferves an Uniformity in its Motion : Whereas 

 a complicated Fever has, befides the Increafe of Motion in 

 the Blood, feveral other Symptoms ; and thefe Difeafes, 

 ■which are Concomitants of fuch X'elocity in the Blood, are 

 often the Caufe of thofe Fevers, in which the Motion of 

 the Blood is not regularly and uniformly augmented, but is 

 diforderly, admitting of divers Periods. 



.J, _ The Blood, as all other Fluids, being 



t/a w'* '*' niade up of liquid Parts, is therefore capably 

 of being put into a more than ordinary de- 

 gree of Motion, both by external and internal Caufes : 

 When the Caufe happens to be fimple and external, as for 

 Inftance, when the Blood is violently agitated, and put in 

 Motion by the Heat of the Sun, or by violent and exceC- 

 fivc Exercife, then the Fever will be only fimple : In fuch 

 a Cafe the Blood is melted, and, like Wax, requires more 

 Space in the Veflels, than when in its ordinary Stale ; and 

 likewife as it becomes more thin and fluid, its Motion in-i 

 creaies ; which is obvious enough, becaufe all thin Liquors 

 will mcve with more Velocity and Swiftnefs than thofe 

 that are thick ; and becaufe a Liquor that is of a thin 

 Texture, will pafs through thofe that are more large, with- 

 out any Oppofition ; therefore all fuch Fevers are regular 

 and uniform. But when a Fever proceeds from any ill 

 Qu:ility in the Blood, as for Infl"ance, if the Blood be too 

 thick or vifcid, fo as to occafion ObftrucTtions in thofe 

 Vellclsthat are the mod minute and fmall, the Blood be- 

 ing oblbuded there, and meeting with Oppofition, muft 

 liseds occafion great diforders, while it flows in greater 

 Quantity than ordinary into particular Parts, and while it 

 endeavours to find out proper Vents and Paflages for itfelf. 

 Now in both thefe Cafes, the glandular Difcharges muft, 

 in a great Meafure, be hurt. But in thofe Fevers that are 

 complicated, fome of thcie Vents may be too much ob- 

 Urudted, while others are too free and open. And hence 

 it is, that Nature is fo much put to it in all Fevers ; for 

 in thofe that are the moft fimple, flie is overpower 'd by a 

 too great quantity of Blood, occafion'd by a too great Rare- 

 faclion, wliereby it takes up more Space than ufual in all 



the 



