HORSE MANAGEMENT, ETC. 403 
‘“‘Tke weight of an animal being ascertained tc be seventy- 
nine pounds, a puncture was made with a lancet into the jugular, 
from which the blood flowed in a very free stream, and was col- 
lected. The vein having ceased to bleed, the caroted artery of 
the same side was divided, but no blood came from it. Ina few 
seconds afterward the animal was dead The weight of the car- 
cass was found to be seventy-three and one-half pounds ; conse- 
quently, the animal had sustained a loss of 5.12 pounds, precisely 
the measure of the blood drawn. 
It appears, therefore, from this experiment, that an animal will 
lose one-fifteenth of its weight of blood ere it dies, although 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 experiments 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 common sized horse at about 12 cwt., the whole 
quantity of blood will amount to 84 quarts, or 168 pounds, of 
which about 45 quarts, or 90 pounds, will flow from the jugular 
vein prior to death, though the loss of a much smaller quantity 
will sometimes deprive the animal of life.”’ 
THe RAPIDITY OF THE CIRCULATION. 
In 1827, Hertne,* a German physiologist, performed the ex- 
periment of injecting into the jugular vein of a dog a harmless 
substance, which could be easily recognized by its chemical reac- 
tions, and noted the time which elapsed before it could be de- 
tected in the vein of the opposite side. This gave the first correct 
idea of the rapidity of the circulation ; for though the older phys- 
iologists had studied the subject, their estimates were founded on 
calculations which had no accurate basis, and gave very different 
results. The experiment of Herine is often roughly performed 
as a physiological demonstration, and we have thus had frequent 
ocvasion, in a general way, to verify its accuracy. If, for ex- 
ample, we expose both jugulars of a dog, inject ints one a solution 
of ferro-cyanide of potassium in water, and draw a specimen of 
* Milne-Edwards, 
