322 EXPERIMENTAL PHARMACOLOGY 



EXPERIMENT LXXIX. 



Lobeline. (Frog or Turtle: Heart and Inhibitory Nerves.) 



1. Pith a frog or turtle and take a heart tracing includ- 

 ing both vagus and crescent stimulation records. Make up 

 a solution of lobeline sulphate containing approximately 

 one milligram of the drug to one cubic centimeter of dis- 

 tilled water. Lobeline sulphate is a dark, thick, viscid sub- 

 stance and is difficult to weigh or measure but dissolves 

 readily in water. 



While taking a record on the drum pour a few drops of 

 the solution on the heart. Do vou note anv immediate 



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action? Stimulate the vagus nerve and note the action on 

 the heart. Now stimulate the crescent and see if you ob- 

 tain the usual result. What conclusions can A^OU draw? 



ml 



Have you obtained similar results with any other drug? 

 Could you prove your conclusions in any other way? Ap- 

 ply more of the drug to the heart to see the later results. 

 How does lobeline act? (See Edmunds: American Journal 

 of Physiology, xi, p. 79.) 



EXPERIMENT LXXX. 



Lobeline, Pilocarpine. (Turtle: Lung Tracing.) 



1. Arrange a turtle for taking lung tracings (consult 

 Experiment LXXIV, 1). When all adjustments are made 

 take one-half inch of the normal (quiescent) record and 

 then inject into the ventricle with a very fine-pointed hypo- 

 dermic syringe one or two cubic centimeters of lobeline 

 solution (one cubic centimeter equals one-half milligram). 

 Do not disturb the lung tracing by manipulating the heart 

 carelessly. Do you get a satisfactory lung record? How 

 do you explain this action of the drug? On what structures 

 does lobeline act? Where are these structures located in 



