on the other fide m anfwer it may be urg d , that the ap- 
pearance is not conflant in diffeilions of Bodys fo af- 
tedred, and that very frequently nothing like it has oc- 
curr'd; from whence we have reafon to conjedure, the 
outward contact of the Air preffing the lurface of the emit- 
ted B!ood,or lome other external Cauje may have an inter- 
eft m forming that shin.ioT elfe why Ihould notthe like con- 
cretion proceed conttantly in the Blood-veff^ds, whence Air 
is excluded as well as when the blood is expos din aPorringer, 
Bnt moreover whoever confults the Practical Anatomy of 
Bonetus on the fubjed:, will find that thele pituitous Bodys 
fcarce ever offer themfelves in dilTedion of: pleuritical per- 
fonsbut" where t\itFleurifywas complicated withkmQ other 
long fettled ind'Apofition J fo that the time of their growth 
cannot be certainly coUeded from fuch Inflames ; Befides 
when they do chance to appearin a fingIePleurifie,theyfloat 
loofe in the mafs of Blood without fixing to any part, are 
of a very lax texture, without any diftinguiftiable Fibres, 
and like what cavers pleuritical Blood in a porringer do 
rather refemble a ftiffer fort of Jelly or Size almoft dry'd, 
than any thing of a tough and fibrous confiftence, inch 
as was obferv'd in the Polypus now defcrib'd. 
I^rfyingius in the 73 of his anatomical Obfervations^ 
i^i^^^r/y ^^^;^/^/ the exiftenee of any fuch matter in a living 
Body, and to confirm his Opinion alTerts it in his own 
power, to make fuch Concretions at pleafure by the known 
Experiment of InjeBing Spirit of Vitriol into a dogs veins, 
andobferving the quick coagulation fo made infers that 
fome peccant acid in the blood occafion d by a difeaie,may 
as fuddenly produce the fame when life is gone. 
In aiilwerto this argument it might: be urg'd, (u hat 
frequent experience has taught us here inEngland, and 
what Kjrl^ingius himfelf feems to hint by his own ex- 
prellionsin defcribing theexperimentj that this artificial 
Polypus is only a kind of grumous and ftrongly concre- 
ted blood, wholly different as to colour, texture, and 
firmnefs 
