when extravasated into the urinary Bladder. 491 
the coagulum remaining so long undissolved in the second ex- 
periment depended upon its being mixed with the urine, I was 
desirous of knowing whether it was the urine incorporated 
with the coagulum, or that which surrounded it, which pro- 
duced this effect. To determine this point I instituted the fol- 
lowing experiment. 
Experiment iv. Four ounces of blood were drawn from the 
arm into a cup, and allowed to coagulate. 4 ounces more 
were drawn into a separate cup. From each of these equal 
portions of coagulum, at the end of three hours, 1 ounce of 
serum was separated, and poured off. To one of them fresh 
urine was added ; to the other common water. The urine and 
water were changed night and morning. 
The water was tinged of a bright red colour throughout the 
whole experiment, and deposited no sediment. On the eighth 
day the coagulum was rather looser in its texture. On the 
thirteenth day it began to break, and by the twentieth day it 
was nearly dissolved. The progress corresponding with that 
of the coagulum in Experiment 111. 
The urine the second day of the experiment was clear, but 
the bottom of the bason was covered with red globules, undis- 
solved. 
On the fifth day, the urine poured off was tinged of a bright 
red colour, similar to the water taken from the other coagu- 
lum ; and after standing some hours a white sediment was 
deposited. 
On the thirteenth day it was looser in texture, and more 
dissolved than the coagulum in the water. It continued to 
tinge the urine of a bright red colour, and what was poured 
off deposited a white sediment in greater quantity. On the 
