22 



Dr J olin Davy on the Blood. 



evaporated at a low temperature ; now on examination, 

 wlnlst still warm, using a J-incli power, not a trace of 

 muriate of ammonia was visible. After ten minutes' 

 exposure, another glass was removed ; the result was similar. 

 After fifteen minutes, the third was examined ; now, t i j 

 were traces of the salt in unmistakable crystals. A irefsii 

 plate with acid was now put on the first cup, and left on five 

 minutes ; on evaporation, a distinct formation of the salt 

 was found on the glass. 



In further illustration of the rapid manner in which 

 ammonia is formed and evolved in connection with the 

 change which takes place in animal matter after deprivation 

 of life, I shall mention another experiment, made when 

 the temperature of the air was 64°. A portion of muscle, 

 with a little fat (together equal in weight to 90 '7 grs.), was 

 taken from the leg of a lamb in less then ten minutes after 

 it had been killed by the butcher ; the fiesh was still warm. 

 After fifteen minutes (the time taken in bringing it from the 

 slaughter-house) it was put into a small low cup and covered, 

 without being in contact, with a plate of glass moistened 

 with dilute acid. After an hour, the glass was taken off 

 and the acid evaporated ; a distinct trace of muriate of 

 ammonia was left. The experiment was repeated ; the 

 glass was left on for two hours and twenty minutes : now, 

 the result, as shown by the crystals formed on evaporation, 

 was still more strongly marked. It was again repeated 

 without delay, and the glass was left on from 6.4 p.m., to 

 12 P.M. The formation of crystals now obtained on eva- 

 poration was copious ; they were, as seen with the J-inch 

 power, large and characteristic, and yet the meat was not 

 apparently the least tainted ; it had undergone during the 

 time — -altogether about nine hours — no change of colour, 

 and had not acquired the slightest unpleasant smell. 



Need I point out the bearing of the results of these experi- 

 ments on those of Dr Hammond ? If he delayed examining 

 the blood for two or three hours, and more especially if his 

 experiments were made during the summer, his finding 

 ammonia in the vapour of fowl's blood is no more than might 

 be expected. 



Still, it may be said, it is open to question whether 



