118 ON THE COAGULATION OF THE BLOOD 
of its leaving the vessels of my finger, and I found that the high temperature, 
though under such circumstances it could not possibly dissipate any ammonia 
from the blood, yet accelerated its coagulation in precisely the same way as 
when it was applied to blood in watch-glasses exposed to the air. 
It is clear, then, that the promotion of the solidification of fibrine by heat 
is as independent of the evolution of ammonia as the coagulation of albumen 
under the same agency. Indeed, it seems probable that the two cases are 
analogous, except that a higher temperature is required in the one than in 
the other. 
When fine tubes containing blood were placed in liquor ammoniae, the 
alkali acted only upon those parts which were close to the ends of the tubes ; 
a very small portion was rendered brown by it, and beyond that a little was 
kept permanently fluid, but the chief length of the blood in the tube was un- 
affected. Having thus ascertained that ammonia travels so slowly along tubes 
of this capillary fineness, I thought I might have an opportunity of giving the 
ammonia theory a fair test by tying such a tube as has been above described 
into the jugular vein of a rabbit and filling it directly from the vessel, and then ~ 
ascertaining whether there was any evidence of retardation of coagulation in 
the blood thus imprisoned. But I could discover no such evidence, although 
I sought for it in confirmation of a view I then held. To this, however, there 
is one special exception to be made, viz. in the case of asphyxia. I found that 
if two such tubes were filled from the same blood-vessel of a creature, one under 
normal circumstances, and the other after asphyxia had been induced, there 
was a most remarkable difference between the rates of coagulation of the blood 
in the two tubes, the asphyxial blood coagulating very much more slowly than 
the ordinary blood ; but when the asphyxial blood was shed into a watch-glass 
and air was blown through it, it coagulated rapidly, showing that in the state 
of asphyxia there must be some volatile element in the blood which has an 
effect in retarding coagulation. 
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 Wolfe’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, 
