26 



Dr John Davy on the Blood. 



equal in quantity, was subjected to the same trial, and for 

 about the same time ; it afforded a tolerably distinct trace 

 of muriate of ammonia. Fresh glasses were applied, and 

 it may be generally remarked, that the indications of the 

 evolution of the volatile alkali increased pretty regularly 

 from hour to hour. 



2. Of the Buck. — When the open air was 40°, a duck of 

 about three months old was killed in the same manner as 

 the fowl. The blood, as it flowed, was received into two 

 wine-glasses, and into a smaller glass, in each of which it 

 was subjected to the same treatment as the preceding. In 

 the first glass, it coagulated in about two minutes ; in the 

 second, there was a slight retardation ; in the third, the 

 retardation reached about ten minutes. The blood which 

 flowed first was brightest. The plates of glass, moistened 

 with acid, were examined after about ten minutes' exposure. 

 On that from the first, not a trace of the salt could be de- 

 tected under the high power ; on that from the second and 

 third, a slight trace was visible ; on repetition, and four 

 hours exposure (this in a room tlie temperature of which 

 was 50°, the first was in the open air), a trace of salt was 

 obtained from each portion, strong from the second, and in 

 proportion to quantity of blood ; also from the third, but 

 very slight from the first. In this, as in the preceding 

 example, the saline formation obtained by repetition of the 

 trials increased, and the more rapidly as putridity advanced. 



3. Of the Horse. — When the open air was 65°, three 

 ounces of blood were taken from the jugular vein of a car- 

 riage-horse. A prepared plate of glass was instantly placed 

 over it. After half an hour, when the blood had coagu- 

 lated, and when the buflfy coat that had formed was equal 

 nearly in thickness to the crassamentum which had sub- 

 sided, an examination for ammonia was made ; barely a 

 trace of it was discernible, no crystals could be detected, 

 merely numerous minute granules. On a fresh glass, after 

 thirty minutes, a distinct trace was obtained, and in a crys- 

 talline form. The trial was repeated as many as four 

 different times in the twenty-four hours. The saline for- 

 mation was found to increase in quantity with the lapse of 

 time. In the last, the crystals of muriate of ammonia, as 



