(_a_). On the 25th of September, 1848, having procured four small
vessels of equal sizes, I placed in the first some dilute sulphuric
acid, in the second some offensive pus, and in the third some water.
The fourth vessel was left empty. They were then all equally warmed,
and some blood from the jugular vein of a healthy horse was received
into each of them so as to fill them to the same level. They were now
stirred with separate pieces of wood. At the expiration of two minutes
(noted by a watch), the contents of the second vessel had become
coagulated into one uniform mass. The contents of the first vessel
(containing the acid) were thickened and of a dark brown colour; in
the third and fourth cups the blood was of its natural fluidity, but
darker coloured in the cup containing water than in the other. At the
expiration of ten minutes, the blood contained in the fourth cup had
begun to coagulate; the blood and water still remained fluid. At the
expiration of a quarter of an hour, the blood had completely coagulated
in the fourth cup, containing blood alone; and had very partially
coagulated in the third cup containing the blood and water.
(_b_). Four vessels were taken, each capable of holding three fluid
ounces. In the first was placed half an ounce of cold water, in the
second half an ounce of dilute sulphuric acid, and in the third half a
drachm of pus, which was quite fresh and sweet. All the vessels were
then quickly filled with blood, from the jugular vein of a horse. The
contents of each vessel were stirred. The blood and dilute sulphuric
acid became thick, and changed in colour almost immediately, as in the
first experiment, but did not coagulate. The pus and blood coagulated
in six minutes, and the mass was firm in seven. The pure blood
coagulated in twelve minutes and was firm in sixteen. The blood and
water coagulated in about the same time, but took nineteen minutes to
become firm.
The above and the following experiments were made at the suggestion of
the author, in conjunction with Mr. T. W. Mayer,[26] veterinary surgeon.
[26] The present mayor of Newcastle-under-Lyme.