312 
COAGULATION OF THE BLOOD. 
simple experiments prove conclusively that cold maintains 
the fluidity of the blood in some manner unconnected with 
any influence it may exert upon ammonia. 
Then, again, I varied the experiment in this way. I placed 
such little tubes of blood in baths of liquor ammoniae at 
different temperatures. By careful management, guarding 
against the volatilization of ammonia, and consequent reduc¬ 
tion of temperature, I succeeded in employing satisfactorily 
a bath of liquor ammoniae at 100° Fahr., the blood being in the 
bath within a few seconds 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 
fibrin 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 unaffected. 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 crea¬ 
ture, and 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 w r atch-glass, and air was blown through 
it, it coagulated rapidly, showing that in the state of a- 
sphyxia there must be some volatile element in the blood 
which has an effect in retarding coagulation. 
