and Experiments on Pus . 307 
the square pieces being removed, were found wet with a 
limpid fluid. In this state they were inspected by the micro- 
scope, by which numerous globules were seen. In ten 
minutes further the liquid was no longer limpid but opaque like 
pus, in which the usual spherical particles were seen with the 
microscope as just mentioned. 
Supposing objections might be offered on account of the 
alteration of texture of the skin employed, square pieces 
of glass were also applied. The results were the same in 
both trials. The two gentlemen above named, as well as 
Dr. Richard Harrison, and other pupils, who happened 
to be present, all concurred in the observation, that the 
limpid matter became opaque, and that while limpid it was, 
like pus, full of spherical particles. 
Sect. VII. Conclusions . 
The statement of the properties of pus in the foregoing 
inquiry I hope will be found to be true ; and I submit to the 
judgment of others whether or no the following inferences 
are legitimately established. 
1. That this fluid essentially consists of three distinct sub- 
stances, viz. 1. An animal oxide, which, among other proper- 
ties, is distinguished by its being white, opaque, smooth, of 
the form of fine curdy particles in water ; not dissoluble in 
less than 1000 cold waters; not coagulable into one mass like 
serum of blood by caloric, alcohol, &c.; only rendered more 
curdy by water of 160 0 to 170°; but readily diffusible.— -2. A 
limpid fluid resembling serum of blood in its impregnations 
and in its coagulability by caloric, alcohol, &c.; in which the 
opaque oxide is diffusible but not dissoluble, and which is spe- 
cifically lighter than that oxide.— 3. Innumerable spherical 
