1835.] 



Blood by repeated Bleedings. 



33 



The serum had at the third bleeding, a specific gravity of 

 1-020, and at the fourth, of 1*017. At the third bleeding, 

 the specific gravity of the blood itself was 1*031. 



The next calf whose blood was examined, was nine weeks 

 old. I did not procure any blood from the first bleeding. 

 The third bleeding was twenty- four hours after the second, 

 and during that period, the animal was once fed ; twelve 

 hours afterwards it was bled a fourth time, but it received 

 no more food : 



SERUM. 



The albumen and salts it is evident, decrease at each 

 bleeding ; the diminution is, however, very variable, and 

 even after the fourth time, does not amount to one per 

 cent, and a half. In the globules, the same diminution takes 

 place, but to such a degree that they are at least reduced 

 to less than one half their original quantity. To this prin- 

 ciple, a remarkable exception occurs in the composition of 

 the blood taken at the last bleeding of the second calf, 

 where the globules are slightly increased above the pre- 

 ceding analysis ; but it will be observed, that the animal 

 received no food during the intervening period, from which 

 the blood might obtain a fresh supply of serum, while the 

 tendency of the different excretions of the animal was to 

 drain from the circulating mass its aqueous part, and thus 

 to increase the apparent quantity of the globules. This 

 explanation is confirmed by the following analysis. 



A calf three weeks old was bled twice before it was 



VOL. I. d 



