Dr. Pearson's Observations , &c. 
The colour was yellowish —the smell was fleshy when 
warmed— it was smooth and unctuous to the touch. 
2. The specific gravity of two different portions, was as 
1630 and 1 633, that of distilled water being 1580 ; each 
substance being of the same temperature. Serum of the blood 
of different patients, was found at the same time to be 1626, 
1627, and 1630. Accordingly, the distilled water being 1000, 
the pus is 1031, and 1033 ; and the serum is 1029, and 1031. 
3. After 12 hours repose, about two ounces by measure 
of a limpid fluid having appeared on the top, it was decanted 
from 01T the opaque purulent fluid ; which was become thinner 
in the upper part of the vessel containing it, and thicker in 
the lower than before. 
4. On further repose, it did not become offensive so soon 
as a portion of the same pus mixed with a little blood, nor 
as serum alone. 
3. This pus neither indicated acidity nor alkalescency to 
the usual tests, viz. turnsole paper, tincture of red cabbage. 
Brazil-wood paper, and turmeric paper. I have, in other 
instances sometimes, observed acidity to be indicated by 
turnsole paper ; but in none alkalescency, so long as the 
matter remained without foetor. 
6 . Being examined under the microscope, when duly 
diluted with distilled water, innumerable spherical particles 
were seen, which did not appear altered in figure, nor diminish 
in number by extreme dilution ; that is, they did not appear 
to have been dissolved. 
II. A pint of pus of the second kind, viz. curdy , was afforded 
i>y a psoas abscess. 
The colour was brown. It felt knotty. On pouring from 
Qqs 
