542 EFFECT OF CUTTING OFF THE BLOOD FROM THE BRAIN. 



and twenty-six seconds, although artificial respiration was maintained. 

 These efforts ceased when the ligatures around the innominate and sub- 

 clavian were loosened. 



The ligatures were then remored from the descending aorta and ascend - 

 ino" cava vena, and the innominate and left subclavian arteries were con- 

 stricted, which was followed by respiratory efforts after one minute and six 

 seconds. These efforts ceased when the vessels were freed. 



The innominate artery alone was then constricted, but this seemed to 

 produce no effect, no respiratory efforts being made by the animal for five 

 minutes. At the end of five minutes, the left subclavian artery was con- 

 stricted, the constriction of the innominate artery being maintained. The 

 animal began to make respiratory efforts fifty-three seconds after constric- 

 tion of the subclavian. These efforts ceased on loosening the ligatures. 



Artificial respiration was then stopped, and the animal began to make 

 respiratory efforts in ten seconds. The medulla oblongata was then broken 

 up, and the experiment was concluded. 



In this experiment I had the aid of my able assistant. Dr. C, F. lioberts, 

 and of Mr. Gaspar (jJ-riswold, an advanced laboratory- student. As the ex- 

 periment progressed, it was ascertained that the vessels could be effectually 

 constricted by making traction on the ligatures without tying. The con- 

 striction could then be instant!}^ removed. It was also ascertained that 

 constriction of the veins made no difference in the phenomena observed. 



Experiment II., October 2, 1877. — A medium-sized, full-grown dog was 

 brought completely under the influence of ether. A bellows was fixed in 

 the trachea and the chest and abdomen were opened as in the preceding ex- 

 periment. These preliminary steps were completed at 11.30 a. m. Artifi- 

 cial respiration, which had been kept up with the bellows, was arrested, 

 < and the animal made efforts at respiration in thirty-seven and three-fifths 

 seconds, having previouslj^ been quiet. The innominate artery and the left 

 subclavian artery were then constricted, the artificial respiration being 

 continued, and the animal made respiratory efforts in two minutes and five 

 seconds, having previously been rendered quiet by artificial respiration. 

 After a few respiratory efforts, the ligatures were loosened, and the animal 

 became perfectly quiet, artificial respiration being continued. While the 

 animal was perfectly quiet, artificial respiration being continued, the de- 

 scending aorta was tied in the chest. The aorta was constricted for five 

 minutes, and no effect was observed, artificial respiration being maintained, 

 and the animal remaining perfectly quiet. The heart was then cut out, the 

 system being thus drained of blood, and the animal made respiratory efforts 

 in twenty-five seconds. 



This experiment was a public demonstration made in a lecture before 

 the class at the Bellevue Hospital Medical College ; and I was assisted by 

 Dr. C. F. Eoberts, Mr. Gaspar Griswold, Dr. G. S. Conant, and Mr. W. L. 

 Wardwell. The experiment was essentially a repetition of Experiment I., 

 and the results of the two observations were nearly identical. 



