Dr. Pearson's Observations 
The thick opaque matter, after decanting the limpid fluid, 
coagulated as before said, into a firm mass at 1 65®. 
3. Each of the above four kinds of pus being evaporated to 
dryness, left in no case less than one tenth of its original 
weight, nor more than one sixth ; but most frequently one 
seventh, to one eighth of brittle matter. The smallest pro- 
portion of residue was left by the 3d, or serous kind; the 
largest, by the 2d or curdy. These residues generally 
became rather soft, especially those of the 3d, or the serous 
kind, after exposure to the air. 
4. The opaque part of pus after separating the limpid fluid 
afforded on evaporation about JL to ~ more of brittle residue, 
than an equal weight of the pus itself ; and it remained hard on 
exposure to the air. The limpid fluid evaporated to dryness, 
yielded about one tenth of brittle residue ; which grew moist, 
and sometimes deliquesced, on exposure to the air. 
5. The brittle residues above mentioned (3), being exposed 
to fire in platina crucibles, flamed for some time, emitting 
a very offensive, pungent, empyreumatic smell ; the unin- 
flammable residue being kept in a state of ignition for a 
longer period, what remained at length was fused readily 
from the serous , viz. the third kind of pus ; but in the cases of the 
other exsiccated residues of the 1st, 2d, and 4th kinds of pus, 
they barely were melted, or only became soft and claggy. 
The fused residues from the serous pus , amounted to to 
y T of the exsiccated pus ; and to to ylg. of the original 
purulent matter. Those from the second kind, the curdy, 
amounted to ~ to ■ K I - of the dried matter, and to to -JL_ 
of the pus itself. The fused masses from the 1st and 4th 
kinds of purulent matter, afforded intermediate quantities of 
melted matter between those just mentioned. 
