ON THE COAGULATION OF THE BLOOD 119g 
and then during asphyxia. The same procedure was adopted with a second 
calf, the animal being in each case under chloroform, which does not interfere 
with the development during asphyxia of the peculiarity in the blood above 
alluded to, but I could not find satisfactory evidence of accumulation of am- 
monia ; and without going further into the question at present, I may say 
that it seems much more probable that the effect is due to carbonic acid, which 
is known to have a retarding influence on coagulation, and which probably 
accumulates greatly in asphyxial blood. 
But in justice to the author of the ammonia theory, and to myself, too, 
who at one time expressed a qualified belief in it, it is but fair to say that this 
theory is extremely plausible. It has been well shown by Dr. Richardson that 
ammonia is a substance well fitted to keep the blood fluid if it be present in 
a sufficient quantity. An experiment of my own illustrates very well the same 
point. I drew out a tube about a quarter of an inch in calibre (Fig. 4), so that 
Fic. 4 
while for two inches at one end it retained its original width, the rest (some 
ten inches) was pretty narrow, though far from having the capillary fineness 
of those before described. Into the thick part I introduced a drop of strong 
liquor ammoniae, A, and then securely corked that end of the tube, C. The 
object of this was that there should be a strong ammoniacal atmosphere in the 
narrow part of the tube. I then opened a branch of a vein, V, in the neck of 
a sheep, introduced the narrow end of the tube into the vessel, and pushing 
it in so that its orifice should be in the current of the main trunk of the vein, 
tied it in securely. I then removed the cork and made pressure on the vein 
at the cardiac side, causing the vessel to swell and blood to pass into the fine 
part of the tube, and before the blood had reached the part of the glass mois- 
tened by the ammonia I put in the cork again and withdrew the tube. In 
a short time, on introducing a hook of fine wire into the extremity of the tube, 
I found the blood already coagulated, but on filing off a small portion of the 
tube I found the blood there fluid. The portion of blood thus exposed soon 
coagulated, when, a second small piece of the tube being removed by the file, 
fluid blood was again disclosed, which again soon coagulated ; and this pro- 
ceeding was repeated with the same results time after time, till, near the thick 
