94 REMARKS ON BLOODLETTING. 



pounds, a puncture was made with the lancet into the jugu- 

 lar vein, from which the blood was collected. The vein 

 having ceased to bleed, the carotid artery of the same side 

 was divided, but no blood came from it j in a few seconds 

 afterwards the animal was dead. The weight of the carcass 

 was now found to be 7'3| pounds ; consequently it had sus- 

 tained a loss of 5i pounds, precisely the measure of the blood 

 drawn. It appears from this experiment, that an animal will 

 lose about one fifteenth part of its weight of blood before it 

 dies j though a less quantity may so far debilitate the vital 

 powers, as to be, though less suddenly, equally fatal. In the 

 human subject, the quantity of blood has been computed at 

 about one eighth part of the weight of the body ; and as 

 such an opinion has been broached from the results of experi- 

 ments on quadrupeds, we may fairly take that to be about 

 the proportion of it in the horse ; so that if we estimate the 

 weight of a horse to be 1344 pounds, the whole quantity of 

 blood will amount to 84 quarts, or 168 pounds ; of which 

 about 45 quarts, or 90 pounds, will commonly flow from the 

 jugular vein prior to death ; though the loss of a much less 

 quantity will deprive the animal of life.* 



" It is well known that young animals possess more blood 

 than old, and that they will, perhaps on this account, sustain 

 greater bodily injuries, and bear larger hemorrhages. In the 

 latter, when the body is gradually decaying, and the powers 

 of life declining, the quantity of blood becomes reduced. 

 Mr. Wilson, in his lectures on the blood, &c, says that 'fat 

 animals are found to possess less blood than leaner animals ; 

 and tame animals, which are confined, less blood than wild 

 ones.' The quantity of blood contained in the body of a 

 man, supposing his whole weight to be 168 pounds, may be 

 rated at 21 pounds, or 2 gallons, 2 quarts and 1 pint. Again, 

 granting that a dog weighs 40 pounds, the amount of his blood 

 will be 5 pints ; hence we may reckon the loss of a pint from 



# The author of Hinds's Farriery is in error when he states that two hun- 

 dred and twenty quarts are calculated to reside in a middling-sized horse. 



