404 DADDS VETERINARY MEDICINE AND SURGERY. 



blood from the other, with as little loss of time as possible, it will 

 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- 

 nae 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 colorless 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 rapidity 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 on 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 Hering, and the result' obtained by these two 

 observers nearly correspond. 



Hering made observations on horses by increasing the fre- 

 quency of the pulse, on 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 results were obtained in other experiments. 



The Transfusion of Blood. 



J. Farrell, V. S., has lately been experimenting in an intei - 

 esting department of veterinary science ; namely, the transfusion 

 of equine blood in diseases attended with low, vital action. Tnuis- 



