294 Observations upon the 
and here earth is first deposited ;. the interpo- 
sition of the least portion of muscle is suffi- 
cient to diminish or destroy the activity of the 
vessels here, and to retard or even destroy the 
whole process. When the tumour is com- 
pletely pervaded by blood vessels, we then 
observe it diminish, which shews that absor- 
bent vessels have also made their way ; the 
callous tumour at this period is found detached — 
from the adjacent soft parts, and becomes 
more and more defined, and not till this peri- 
riod do we find it covered with any proper in- 
vesting membrane. ‘This part of the subject 
is so entirely regulated by those laws which 
govern the same process when taking place 
in soft parts, and have been so minutely des- 
cribed by former observers, that I have only 
thought necessary to allude to it in this cur- 
sory manner, in order to connect the subject 
and bring me more naturally to consider the 
origin of that membranous covering which is 
destined to form the future external perioste- 
um of the fractured part. 
Of the membrane investing the callous tumour. 
The further progress of reunion produces 
destruction of that part of the external mem- 
brane which is enveloped in its own effusion, 
