302 EXPERIMENTAL PHARMACOLOGY 



EXPERIMENT LXXIV. 

 Nicotine. (Turtle: Lungs.) 



1. Pith a turtle, brain and cord. Remove the plastron 

 as shown in Fig. 232. Consult also Fig. 233. Arrange a 

 eannula in the wind pipe and a small (very sensitive) 

 tambour to write on the drum. The magnification for the 

 writing point should be large. Partially inflate the 

 lungs (blow them up from the air vent in the tambour 

 tube) and adjust the tambour on the drum. (A heart 

 tracing may be taken also when the nerves are stimulated, 

 but it is difficult to get a satisfactory heart tracing when 

 drugs are injected into the heart. It is possible to inject 

 drugs into the large vein running into the liver but this re- 

 quires considerable care and when lung records only are 

 w r anted the heart is best left alone.) 



Dissect out the vagus and sympathetic nerves on one 

 side of the neck and stimulate them. Do you get a satisfac- 

 tory record? Go far down in the tissues at the side of the 

 neck and find the sympathetic branch which joins a gan- 

 glion on the vago-sympathetic nerves. Stimulate this 

 branch and see if you can get a lung tracing from it. (The 

 opposite lung may be temporarily shut off by a bull-dog 

 on the corresponding bronchus.) 



After one or two records of the lung contraction follow- 

 ing nerve stimulation have been secured then remove the 

 bull-dog from the bronchus, see that both lungs are mod- 

 erately distended and that the tambour is properly ad- 

 justed on the drum. Start the drum and with a fine-pointed 

 hypodermic syringe inject into the ventricle one or two 

 cubic centimeters of one-half per cent nicotine solution. 

 The circulation is sluggish in the turtle and some time may 

 elapse before the drug reaches the lungs. Wait for the 

 effect to come on. Be sure the turtle is in a satisfactory 

 condition (not diseased or weakened in any way) and that 



