COAGULATION OF THE BLOOD. 
313 
Supposing at first that this volatile element must be 
ammonia, I hoped to be able by chemical means to find 
evidence of its accumulation in asphyxia, and thus add a 
fact of great interest to physiology. Imitating experiments 
previously made by Dr. Richardson, I passed air successively 
through blood and through hydrochloric acid, and then 
estimated the amount of ammonia acquired by the latter by 
means of bichloride of platinum. In order to prevent the 
possibility of the loss of any ammonia, I directed blood from 
the carotid artery of a calf fairly into a Woulfe’s bottle by 
means of a vulcanized india-rubber tube tied into the vessel, 
and then drew a certain volume of air through it by means 
of an aspirating jar, the experiment being performed first 
before and then during asphyxia. The same procedure 
was adopted with a second calf, the animal being in each 
case under the influence of chloroform, which does not 
interfere with the development during asphyxia of the pecu¬ 
liarity in the blood above alluded to; but I could not find 
satisfactory evidence of accumulation of ammonia; 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 influ¬ 
ence 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 plau¬ 
sible. 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, so that 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 1 introduced a drop of strong liquor ammoniae, 
and then securely corked that end of the tube. The object 
of this was that there should be a strong ammoniacal atmo¬ 
sphere in the narrow part of the tube. I then opened a 
branch of a vein 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 
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