ACTIOX OF AMYL XITR1TE 



399 



that may occur. Count his pulse and compare with the 

 normal. Be sure to observe his rate and depth of breath- 

 ing as the drug is inhaled. How do you account for the 



changes observed? 



EXPERIMENT CXIX. 

 Amyl Nitrite. (Student: Pulse Tracing.) 



1. Attach a sphygmograph to the wrist as shown in Fig. 

 327. Take one or two normal tracings and then prepare a 

 strip of paper ready to record the action of anryl nitrite on 



Fig. 327. Dudgeon's sphygmograph arranged for recording tracings from the radial pulse. 



the pulse. The subject should be in a perfectly comfort- 

 able position. When all is ready break the pearl or am- 

 poule and let the subject inhale the vapors. When the ef- 

 fects come on markedly (in about ten seconds) start the 

 clock work and run the paper through rapidly to record the 

 changes in the form of the pulse curve. What can you say 

 about the dicrotic wave? What is its origin and sig- 

 nificance? How does anryl nitrite affect it? What other 



