536 
COULON AND OLIVIER. 
The intensity of this process ordinarily gives rise to the forma¬ 
tion of abscesses, quite numerous, circumscribed to the inflamed 
portion; various in size, containing thick, creamy, yellowish pus, 
without special envelop, but surrounded by little purplish granu¬ 
lations. 
This tendency to purulent transformation, characteristic of 
true inflammation, is again found in the lower hepatized part. 
In that region the easily torn lobular tissue exposes a mass of 
tibrinous concretions, soon transforming themselves into purulent 
centres, which are observed as little yellowish drops at the sur¬ 
face of the cut structure. Towards the lower border, these cen¬ 
tres gather together and form little purulent masses, partly con¬ 
creted, and of very irregular shapes. 
Finally, the only lesions common to both affections are the 
modifications of the lobules or centres. 
In pleuro-pneumonia, the sudden and complete enclosing of 
some tubular portions by the infiltrated septa may change them 
into sequestra, and their substance broken down by the peripher- 
ical compression and the capillary hemorrhages, slowly becomes 
soft and appears as a grumulous, greyish liquid, surrounded by a 
fibrous envelope. 
In ordinary pneumonia the cause of this mortification does not 
come from outwards, but from the inside of the lobule ; it is due 
to the fact that the lobules, made autonomous by their enclosing, 
are congested in a proportion that varies and is proportionate to 
the importance of their special vascular system. Those in which 
the congestion has been hemorrhagic to such an extent as to 
break the parenchyma, must mortify rapidly; indeed, they are 
found in the hepatized region, to the state of sequestra separated 
from their walls by a disjointing fissure, in which the substance 
remains for some time dry, as momified, then becomes soft and 
puttaceous in consistency. 
We believe that in the presence of those, the only common 
lesions of the two diseases, when they are found with the others 
so different, no confusion can be made in their diagnosis. 
To resume : Sporadic pneumonia is clearly distinguished from 
pleuro-pneumonia by a total sum of constant lesions, unequivocal, 
and amongst which are : 
