COAGULATION OF TIIE BLOOD. 231 



The blood is then said to be " buffed and cupped." These appear- 

 ances do not present themselves under ordinary conditions, but only 

 when the blood has become altered by disease. 



The entire quantity of blood existing in the body has never been 

 very accurately ascertained. It is not possible to extract the whole 

 of it by opening the large vessels, since a certain portion will always 

 remain in the cavities of the heart, in the veins, and in the capil- 

 laries of the head and abdominal organs. The other methods 

 which have been practised or proposed from time to time are all 

 liable to some practical objection. We have accordingly only 

 been able thus far to ascertain the minimum quantity of blood 

 existing in the body. Weber and Lehmann 1 ascertained as nearly 

 as possible the quantity of blood in two criminals who suffered 

 death by decapitation ; in both of which cases they obtained essen- 

 tially similar results. The body weighed before decapitation 133 

 pounds avoirdupois. The blood which escaped from the vessels at 

 the time of decapitation amounted to 12.27 pounds. In order to 

 estimate the quantity of blood which remained in the vessels, the 

 experimenters then injected the arteries of the head and trunk with 

 water, collected the watery fluid as it escaped from the veins, and 

 ascertained how much solid matter it held in solution. This 

 amounted to 477.22 grains, which corresponded to 4.38 pounds of 

 blood. The result of the experiment is therefore as follows : 



Blood which escaped from the vessels 12.27 pounds. 



" remained in the body 4.38 " 



Whole quantity of blood in the living body, 16.65 



The weight of the blood, then, in proportion to the entire weight 

 of the body, was as 1 : 8 ; and the body of a healthy man, weighing 

 140 pounds, will therefore contain on the average at least 17 J 

 pounds of blood. 



1 Physiological Chemistry, vol. i. p. 638. 



