592 [June 11, 



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 coagu- 

 lation of albumen undef 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 unaifected. 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 coagu- 

 lated 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 accumula- 

 tion 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 



