Dr John Davy on the Blood. 



27 



seen with the high power, were numerous and large, and 

 yet the glass had increased in weight only '01 grain. 



4. Of the Sheep. — When the temperature of the air was 

 about 70°, two portions of blood were obtained from a sheep 

 of about three years old, one portion just after the great 

 cervical vessels had been divided — this chiefly arterial ; 

 another when the flow of blood had become languid— this 

 of a darker hue, and, it may be inferred, chiefly venous. 

 The quantity of each was about three ounces ; they were 

 tested in the same manner as the preceding. The first 

 examination was made after an hour. From the arterial 

 blood a very few and minute crystals of muriate of ammonia 

 were obtained ; from the venous, more. The difference 

 was well marked. After two hours, and again after sixteen 

 hours, the trial was repeated. Each time there was an 

 increase of the salt, and in a somewhat larger proportion 

 from the venous than from the arterial. 



5. Of the Calf — The temperature of the air was about 

 the same as the last mentioned, as was also the quantity of 

 blood, which was the first that flowed. Examined after an 

 hour, a distinct but very minute formation of muriate of 

 ammonia was detected. Examined a second and a third 

 time, after the same intervals as the sheep's blood, the 

 results were very similar. The increase of weight after the 

 last and longest interval did not exceed 0*01 grain. 



6. Of the Bulloch. — The air was about 65°. The quantity 

 of blood collected was five ounces ; it had the character of 

 venous blood, having been obtained when the flow had 

 nearly ceased. Examined after eight minutes, distinct 

 crystals of muriate of ammonia v/ere seen on the glass more 

 than in any of the preceding trials. Again, examined at 

 intervals during the twenty-four hours, the results were 

 much the same as the preceding, the quantity of saline 

 matter increasing with the length of time. On the last 

 glass its proportion was greater than in any of the fore- 

 going ; the crystals were distinguishable by the naked 

 eye.* 



Of these specimens of blood, the sheep's bore distinct marks of putridity, 

 as indicated by smell and discoloration (reddening of the sernm) somewhat 

 earlier than the bullock's ; the bullock's than the calf's and horse's. On the 



