404 EXPERIMENTAL PHARMACOLOGY 



EXPERIMENT CXX1II. 



Amyl Nitrite, Nitroglycerine, Sodium Nitrite. (Dog: 



Blood-pressure, Respiration, Spleen or Intestinal 



Loop Volume, Blood.) 



1. Prepare a dog for recording blood-pressure, respira- 

 tion and the volume of either the spleen or a small loop of 

 the intestine. The injecting burettes contain nitroglycerine 

 (one-fourth per cent the U. S. P. form is one per cent) 

 and sodium nitrite (one per cent). Place a straight cannula 

 in one femoral artery pointing toward the heart. Into a 

 test tube draw off through this cannula five cubic centi- 

 meters of blood and add to the blood two cubic centimeters 

 of two per cent sodium chloride solution. Set the tube 

 aside and draw off five more cubic centimeters of blood into 

 a second test tube. Add to this tube two cubic centimeters 

 of two per cent sodium nitrite solution. Shake up both 

 tubes and let them stand for some time. Do you note any 

 changes in either one ! If so what and how marked is the 

 change? If a spectroscope is available a one-half or one 

 per cent solution of each may be made and compared as 

 regards their spectra after the remainder of the experi- 

 ment is finished. 



Take a normal record and prepare to give the animal 

 some amyl nitrite. Proceed with this as follows : Keep the 

 anesthesia as regular as possible. Open the side tube of 

 the tracheal cannula and let the animal breathe mainly 

 through this. Place a pearl on a towel and seize the pearl 

 with a pair of forceps through the towel from below. In- 

 vert the towel so as to form a very small tent-like chamber 

 over the end of the side tube of the tracheal cannula. Be 

 sure glass particles do not fly into the wind pipe. AVhen all 

 is ready (a good normal record is being taken) snap the 

 pearl and let the animal breathe the vapors. The effect 

 should come on promptly. It will not last long and after 



