204 DADD’S VETERINARY MEDICINE AND SURGERY. 
blood from the other, with as little loss of time as possixle, it wil 
be found that, in twenty or thirty seconds after the injection, the 
salt has had time to pass from the jugular to the right side of the 
heart, thence to the lungs and left side of the heart, and from 
this, through the capillaries of the head and face, back to the 
jugular on the opposite side. Its presence can be determined by 
the distinct blue color produced on the addition of the perchlo- 
ride of iron to the serum, if the specimen be allowed to stand, or 
a clear extract of the blood be made by boiling with a little sul- 
phate of soda and filtering, treating the cvlorless liquid thus ob- 
tained with the salt of iron. The experiments of HERING were 
evidently conducted with great care and accuracy. He drew 
blood at intervals of five seconds after the commencement of the 
injection, and thus, by repeated observations, ascertained pretty 
nearly the rapiatity of the circuit of blood in the animals on which 
he experimented. Others have taken up these investigations, and 
introduced some modifications in the manipulations. VIERORDT 
collected the blood as it flowed, in little vessels fixed op a disk 
revolving at a known rate, which gave a little more exactness to 
the observations; but the method is essentially the same as that 
employed by Herine, and the results obtained by these two 
observers nearly corresponil. 
HeErrtn@ made observations on horses by increasing the fre- 
queucy of the pulse, ou the one hand, physiologically, by exercise, 
and, on the other hand, pathologically, by inducing inflammation, 
He found, in the first instance, that in a horse, with the heart 
beating at the rate of thirty-six per minute, with eight respira- 
tory acts, ferro-cyanide of potassium injected into the jugular ap- 
peared on the vessels on the opposite side, after an interval of 
from twenty to twenty-five seconds. By exercise, the number of 
pulsations was raised to one hundred per minute, and the rapidity 
of the circulation was from fifteen to twenty seconds. The obser- 
vations were made with an interval of twenty-four hours, The 
same resulta were obtained in other experiments, 
THE TRANSFUSION OF BLOoop. 
J. FaRRELL, V.S., has lately been experimenting in an inter- 
esting department of veterinary science ; namely, the transfusion 
of equine blood in diseases attended with low, vital action, Trans 
