I M PROVED. 175 



And thus we may undcrflaiid how a Liquor thick- 

 er thp.n the Blood itielf may be ftniin'd oft from th« 

 Blood, if the Orifice of the Gland be fo big as to 

 admit Particles of any Sizes, and the Branches fo 

 numerous as to draw off the thinner Parts, before 

 the thicker arrive at the Excretory Du6l. 



I could f irther illv.flrate this Theory by Diagrams, 

 and fliew ir;ore plainly how. znd in what Manner, 

 the fcveral HunriOurs in the Body may be feparated 

 from the Blood, which muft cither be compofed of 

 fo many Humours as are feparated from it, or other- 

 wife it mufL contain a few Principles, which mixed 

 all together fcrm the Blood, and which, \'arioufly 

 combined, form the different Humours which are 

 drain'd frcm it ; as a few Kays of Light, of diffe- An Obar- 

 rent Refrangibilities, mixed all together, produce a ^^J^'^J^„ ,,^ 

 white Colour, but varioufly combined exhibit all '' 

 imaginable Variety of Colours. And it is not at allTheGla .;:.- 

 probable, that the Blood, in which we difcern butf-r^^^^t 

 two diftind Parts, fliould be compofed of near thirty r^^j^f^j^J '^ [ [\ 

 f.mple Plumours ; for fo many do the Glands fepa- i-,^ours • o •-. 

 rate from it : Nor is it agreeable to that Simplicity tht Bicv-. 

 which Nature conllantly afrc«Sls in all her Operations. 



The Principles of all Natural Bodies ?ue faid not 

 to cxccfd five ; and hew prodigious is the Variety 

 that refults frcm their different Mixtures and Modi- 

 fications ? 



If we fappofe likewife but five Principles or dif- 

 ferent Particles in the Blood, their Combinations a- 

 lone, with different Modifications and Proportions, 

 will yield near as many different Plumours as are fe- 

 parated from the Blood. And it is Matter of Fa6l, 

 that Urine, Sweat, Tears, Salit^a or Spittle in 

 Man, and v/hat v\c call Sla-z-er in Horfes, as well 

 as the Milk in Human and Brute Creatures, are 

 Compound Liquors, and that in each of them there 

 are Parts common to all of them. And if the Com- 

 pofition of feme other HumiOurs of the Body is not 

 altogether fo plain and apparent as in thefe I juil 

 mcntion'd, yet it does not follow from thence, that 

 I 3 they 



