584 



[June 11; 



Yet it by no means follows that the vital theory and the ammonia 

 theory are necessarily altogether inconsistent. It might be true for 

 anything we could tell, a priori, that the coagulation of the blood, 

 when shed from the body, might depend on the evolution of a certain 

 amount of ammonia, previously holding the fibrin in solution, and 

 yet it might, at the same time, be true that the cause of the am- 

 monia remaining in the blood in the healthy vessels might be an 

 action of the living vessels retaining it there. It might be that an 

 action of the living vessels might chain down the ammonia and pre- 

 vent it from escaping, whereas, when shed from the body, it would 

 be free to escape. 



This notion was, I confess, at one time entertained by myself; 

 and one of my earliest experiments was performed with a view to the 

 corroboration of the ammonia theory as applied to blood outside the 

 body. It seemed to me desirable that further evidence should be 

 afforded of the effect of mere occlusion from air in maintaining the 

 blood fluid. If the ammonia theory were true, then if blood could be 

 shed directly from a living vessel into an air-tight receptacle composed 



Fig. 1, 



of ordinary matter it ought to remain fluid. For this purpose, I made 

 the following experiment : I tied into the jugular vein, V, (fig. 1) of 



