492 ON THE FEMORAL GLAXD OF ORS ITIlOlillVXCllUS, 



Experiment II : A rabbit about 3 lbs. in weight was etherized 

 and cannulfe inserted into the left jugular vein and carotid artery, 

 and a small sharp pointed cannula was passed through the wall 

 of the trachea. The cannula in the trachea was connected by a 

 piece of rubber tube with a small tambour, covered with thin 

 india-rubber sheeting. The movements of the india-rubber 

 were transmitted to a lever, the end of which marked by means 

 of a writing point, on a travelling surface of smoked glazed paper. 

 As the animal sucked in air with each inspiration, the rubber was 

 pulled down and the lever marked a downward stroke on the 

 paper. When air was expelled with each expiration the rubber 

 membrane rose and the lever described an upward stroke. In 

 this way a record showing the extent, frequency and general 

 character of the respiration was obtained. The interior of the 

 artery was connected with a mercury manometer, the movements 

 of the mercury in the distal limb of which were recorded on the 

 paper by means of a light float and stile carrying a writing point. 

 In this manner a record was obtained of the pressure of the blood 

 exerted upon the walls of the vessel (aorta), as well as every 

 variation of this pressure due to the heart's pumping fresh 

 quantities of blood into the aorta at each beat, and to the respira- 

 tory movements of the animal. 



In addition to these records, the time was marked by an 

 electromagnet in connection with a clock, so that at each second 

 a small vertical line was drawn. The exact movement at which 

 the injection was commenced and ended was also indicated by 

 another writing stile, which described a horizontal line on the 

 travelling surface. 



During the injection this stile which was ccmnected with an 

 electromagnet, was raised by closing the circuit and fell again at 

 the termination of the injection when the circuit was opened, by 

 its own weight. In this way the duration of the injection was 

 indicated by raising this horizontal line. The writing points of 

 all four records were previously carefully adjusted so as to register 

 exactly in the same vertical line. 



