Professor Hering an the Circulation of' the Blood. 79 



Passing over the details of the experiments, we arrive at the 

 results obtained by the author. 



1*/, A solution of hydrocyanate of potash and iron, intro- 

 duced into the jugular vein of the horse, runs the course of the 

 circulation, and arrives in the jugular vein of the opposite side, 

 in an interval of' from twenty to twenty-five seconds (Exp. 8, 10, 

 13, 14, 16 > or from twenty-five to thirty (Exp. 12.) It ar- 

 rives in from twenty-three to thirty seconds in the external tho- 

 racic vein of the opposite side (Exp. 5.), in twenty seconds at 

 the vena saphena major (Exp. 4.), in from fifteen to twenty se- 

 conds in the masseteric artery (Exp. 6.), in from ten to fifteen, 

 and in from twenty to twenty-six seconds in the maxillary- arte- 

 ry ; lastly, in from twenty to twenty-five, and from twenty-five 

 to thirty seconds in the metatarsal artery, always on the oppo- 

 site side to the place of injection (Exp. 18, and 16.) 



If the liquid introduced by this mjection is moved by the 

 same means as the blood, the velocity of the motion must be the 

 same in both. It appears that the velocity of this motion is not 

 increased in the ratio of the number of pulsations of the heart ; 

 for in a horse, in which the pulse was sixty in the minute 

 (Exp. 8.), and in two others in which it was from thirty-six to 

 forty-four, and from forty-eight to fifty-two (Exp. 13, and 14.), 

 the results were the same. Yet in another in which the pulse 

 was from thirty to forty-four, the circulation was found to be 

 some seconds slower. 



2c?, The hydrocyanate of potash and iron is promptly secreted 

 by the serous membranes, but in small quantities ; and this in 

 the inverse ratio of their distance from the heart. Thus, the 

 secretion commences by the internal surface of the pericardium, 

 where it is also the most abundant ; it then takes place in the 

 pleura, the peritoneum, and, lastly, in the articular capsules. 

 The cerebral cavities were opened only in a few cases ; and 

 there was never found any trace in them of the saline solution 

 injected. In the other serous cavities, the presence of this so- 

 lution was discovered two, three, four, seven, and fifteen minutes 

 after injection. These moments were also those when the ani- 

 mal ceased to give symptoms of life. 



Sd, The mucous membranes secrete the injected solution less 

 quickly than the serous. A few minutes are, however, suffi- 



