On the Composition of the Blood. 
211 
Amc)n<j the advantages consccjucntly which are derivable from 
bh)()d-letting in inflammatory aflections, we must name that 
which arises from the withdrawal of a portion of this excess 
of fibrine by the operation. The benefit, however, is frequently 
not so great as might at first sight appear, arising from the cir- 
cumstance that so long as inflammation persists, there is a suspen- 
sion of the vital functions of the affected organ, and consequently 
a constant accumulation of fibrine, none of that substance being 
consumed for the nutrition of the diseased organ. 
In diseases of the opposite character to those just alluded to, 
this important element of the liquor sanguinis is diminished in 
quantity, often sinking below even one part in a thousand. 
Hence a deficiency of fibrine is associated with typhoid fevers, as 
likewise with many other diseases of an asthenic nature; which, 
are not found to yield until an increase of the fibrine begins 
again to take place.. 
In the cattle plague of Eastern Europe — the pathology of, 
which terrible scourge was recently investigated and reported 
on by us to the Society, the presence of the materies morhi in 
the blood leads to an exudation of the fibrine from the capillaries 
of the mucous membranes. The blood of such patients does not 
clot after death, but remains perfectly fluid in all the laiger 
vessels, and particularly in the veins, from being thus defri- 
brinated. Convalescence is a sure sign of the reappearance of 
the fibrine ; and if, at that time, blood be experimentally drawn 
from an animal, it will be found to form a soft gelatinous mass, 
the density of which will likewise be in proportion to the extent 
of the re-established health. 
A loss of fibrine also so far alters the viscidity of the blood, 
that it does not circulate so perfectly through the capillaries as 
it otherwise would do, which produces a tendency to conges- 
tions, haemorrhages, &c. 
From what has beer» advanced it will be inferred that nutri- 
tion is mainly due to the fibrine, and as an appropriation of it 
for this purpose takes place in the systemic capillaries proper 
to each organ, so, on comparing its quantity in the arterial with 
that in the venous blood, a slight difference will be observed. 
According to Miiller the proportion is as 29 to 24, the larger 
amount necessarily existing in arterial blood. 
Chemically considered, there is not much difference between 
albumen and fibrine, while, on the contrary, both the physical 
and vital properties of the two fluids vary, as we have seen, to a 
very considerable extent. Much more might be said respecting 
this constituent of the blood, but it is unnecessary to add to 
these remarks, except to state that united with the serum, as we 
find it within the vessels, it constitutes the true liquor sanguinis. 
P 2 
