Sir Everard Home on the 
84 
From this investigation of the blood, it appears that the 
principal materials of which the body is composed, are met 
with in the blood. The fat is by many considered a secretion ; 
for this opinion there is however no foundation. That 
the fat is formed in the colon, and is thence taken up into 
the blood vessels, and distributed to the different parts of 
the body, is sufficiently proved by the mode in which adipo- 
cere is made, and by the observations on the colon in dif- 
ferent animals, that have been long since laid before the 
Society. No direct experiment has been made, that I am ac- 
quainted with, for detecting the presence of fat in the blood ; 
possibly the reason is, that its failure would prove nothing, 
since the blood contains an alkali with which the oil will be- 
come united. That I might not be said to have neglected this 
part of the enquiry, I instituted the following experiment. 
Twelve ounces of blood were drawn from the arm into a 
glass vessel of a globular form capable of containing a pint, 
with a tube rising out of the globe six inches long, and half 
an inch in diameter ; at the end of 24 hours the serum was 
poured off, and the vessel and tube filled up to the orifice 
with distilled water ; after this vessel had remained 24 hours 
at rest, no appearance of oil took place upon the surface. 
The coagulum was then broken down by a long wire, which 
produced an immediate evolvement of carbonic acid gas, 
in such quantity that the water fell in the tube an inch in 
length ; but there was no appearance of oil seen on the 
surface. The blood was examined for several days succes- 
sively ; it became very offensive, but showed no appearance 
of oil. In the blood of the salmon and skate, oil is met 
with in such quantity as to render blotting paper greasy a 
