28 



animal must be owing to the combination of the oxygen 

 of the atmosphere with it. 



EXPERIMENT VII. 



In order to ascertain whether this change wrought 

 on the blood by removing the animal from its place of 

 confinement to the open air — I first took two worms 

 that had been killed by being confined in atmospheric 

 air, and introduced them into a vessel containing 

 nitrogen, where they remained four hours. They 

 were then removed and examined ; but no change of 

 the colour of the blood was discernible. The same 

 animals were introduced into a vessel containing oxy- 

 gen, and permitted to remain the same length of time 

 — were then removed and examined, and there was aii 

 evident change of the blood from a dark to a florid 

 colour — observed by two gentlemen who were also 

 present. I also took some animals that had been con- 

 fined and perished in nitrogen, whose blood was of a 

 dark colour, and put them in a vessel containing oxy- 

 gen ; after remaining in it a few hours it assumed a 

 florid appearance. The same animals were returned 

 into the nitrogen, and the blood lost its bright colour 

 in a considerable degree. 



If the animals are removed from the place of con- 

 finement immediately after death no marks of inflam- 

 mation are present ; but in the space of an hour, gene- 

 rally, there was a perceptible enlargement of the parts 



