DR DAVY’S OBSERVATIONS ON BLOOD AND MILK. 57 
the tube is far more elastic than the other, after the manner of the middle arterial 
coat. 
Other instances might be given, tending to shew the same disposition on the 
part of coagulable lymph to a certain regular arrangement of its parts, as it were, 
of a nisus formativus, in the act of coagulation. In examining the buffy ccat, or 
the fibrinous masses which are so commonly met with after death in the right 
cavities of the heart, it is not uncommon to find in them, when divided, cavities 
containing serum resembling cysts. And in the ventricles of the heart, and the 
aorta and the principal veins, especially the iliac and femoral, fibrinous concre- 
tions, as it is well known, are often found after death from lingering diseases, in 
which a puriloid matter is contained, as in a sac,—a matter which has been imi- 
tated by Mr Gutiiver, by the coction of lymph, at about the temperature of the 
human body, and which, previous to his experiments, had been considered as 
pus, and, erroneously, as the product of inflammation. 
I would ask in conclusion, is not this disposition of coagulable lymph called 
into play in other occasions during life, and may it not serve to explain certain 
appearances which are commonly accounted for in a different manner, such as 
the cysts which so rapidly form in the instance of aneurisms, the consequence 
of wounds, and the lining membrane of the sacs of false aneurisms, which is hardly 
in appearance distinguishable from the inner coat of the artery with which it is 
continuous ? 
4. On the Eject of Serum in promoting the Coagulation of Milk. 
There is a marked difference, as is well known, between the albuminous part of 
the serum of the blood and that of milk,—ordinary cow’s milk,—viz., that, whilst 
the former is coagulated by a temperature below the boiling point of water, the 
latter, in its fresh state, is not so affected, even by ebullition, but, on the contrary, 
has its natural tendency to coagulate, connected with the absorption of oxygen 
and the formation of an acid, retarded. A priori, perhaps, it would harldly be 
expected, as regards the property of coagulation, that the one fluid mixed with 
the other would have any material effect. But that it is not so, I have found on 
trial. Milk, I find, when mixed with serum in certain proportions, is coagulated 
by heat. I shall notice some results obtained, using mixtures of the serum of the 
blood of the sheep, which coagulated at about 170° Fah., and cow’s milk. 
Equal parts of the two remained liquid at 170°, and coagulated about 175°. 
The coagulum was of an opaque white, very little softer than the coagulum of 
the serum alone. Mixed with water it did not render it milky; and the watery 
infusion was not rendered turbid by acetic acid, and only in a very slight degree 
by the nitric acid. 
VOL. XVI. PART I. P 
