1863.] 591 



snapping it across after a scratch with a file, that instead of remain- 

 ing longer fluid than in a watch-glass, the blood in it, being more in 

 contact with the glass, was always more quickly coagulated, while 

 coagulation was still more rapid in the capillary tube, where the blood 

 was still more exposed to the influence of the foreign solid the 

 greater proximity to the liquor ammonia^ having no influence 

 upon it. 



It may perhaps be argued that the drop of blood employed being a 

 small drop, and this small drop having been drawn up by suction into 

 the tube, it might have parted with its ammonia before it got into the 

 tube ; but then (and now comes the bearing of the experiment on the 

 effect of temperature) I found, if I placed a similar tube filled in the 

 same way in a vessel of snow, so as not to freeze it but to keep it ice- 

 cold, the blood in it remained fluid as long as I chose to keep it there. 

 Now if all the ammonia had left the blood before it was introduced into 

 the tube, cold ought, according to the ammonia theory, to have had no 

 effect in retarding its coagulation ; for, according to that theory, cold 

 operates by retaining the ammonia. On the other hand, if we take 

 the other alternative and suppose that any ammonia which the blood 

 might have contained was still in these tubes, the former experiment 

 proves clearly that the retention of ammonia has no effect in produ- 

 cing fluidity no effect in preventing coagulation ; and if the reten- 

 tion of ammonia has no effect in preventing coagulation, then cold 

 certainly cannot prevent coagulation by retaining the ammonia, 

 because, even if retained, it would not influence the result. In what- 

 ever way we look at them, therefore, these simple experiments prove 

 conclusively that cold maintains the fluidity of the blood in some 

 manner unconnected with any influence it may exert upon am- 

 monia. 



Then, again, I varied the experiment in this way. I placed such 

 little tubes of blood in baths of liquor ammonise at different tempera- 

 tures. By careful management, guarding against the volatilization 

 of ammonia and consequent reduction of temperature, I succeeded in 

 employing satisfactorily a bath of liquor ammonise at 100 F., the 

 blood being in the bath within a few seconds of its leaving the ves- 

 sels of my finger, and I found that the high temperature, though 

 under such circumstances it could not possibly dissipate any ammonia 



