100 
ON ABSCESS. 
sionally of its colouring matter ; the infiltrated fluid so separat- 
ing and uniting with the tissues of the part, as to destroy all 
traces of its former organization. In the centre of the inflamed 
structure this softened pulpy mass is changed into pus, not by a 
conversion of the tissues themselves into fluid, but by fluid from the 
capillaries, dissolving, in some degree, the structure or membrane 
into which it is poured, and the cellular tissue being softened and 
disorganized; the vessels of the surrounding structure, not exhausted 
of their vitality, pour out coagulable lymph, which forms a barrier 
to the opposing fluid, and prevents its extension : at the same time 
the increasing effusion of purulent fluid is solidifying the cellular 
tissue, producing pressure in all directions ; and the further depo- 
sition of coagulable lymph, causing an increase in the walls of the 
abscess, are aiding to accomplish this end. In this manner the 
further disorganization and defilement of the neighbouring struc- 
tures is prevented ; effects which sometimes happen in those con- 
stitutions where the vital energies, and state of local action, are 
incapable of the formation of coagulable lymph, by which the de- 
fence to extending disease is formed. The dissemination of the 
minute accumulations of sero-sanguineous or sero-albuminous 
matter, especially in the softest, and first and most intensely in- 
flamed part, appears to be the first step of the suppurative pro- 
cess. The fluid gradually becomes more plentiful, and thus these 
minute collections enlarge, advance towards each other, and ulti- 
mately become one cavity, by the tissue constituting the partitions 
between them disappearing from softening and disorganization of 
its substance. 
As the disease progresses, the thin albuminous fluid contained 
in the cavity becomes pus ; the fluid loses its colouring principle, 
the shreds of the cellular tissue are fully dissolved, and the pus 
may be said to be thoroughly compounded ; and when the whole 
process is complete, pus constitutes a peculiar fluid, differing in 
and possessing specific characters sufficiently distinguishing it from 
every other fluid of the body. 
Pus, taken from an abscess such as I have been describing, fully 
matured and elaborated, on examination will be found to possess 
the following characteristics : — in colour it is whitish, and similar 
in appearance to cream ; agreeable to the smell, unless exposed 
to the air. Its touch is smooth and soft, something heavier than 
water, and but partially soluble in that element ; homogeneous, 
friable when dried, but does not coagulate, nor does it readily run 
into putrefaction ; and of itself produces no irritation in the con- 
taining tissues, unless exposed to atmospheric influence. Micro- 
scopic examination gives minute colourless globules, like unto 
those observed in the blood , and a colourless fluid in which the 
