ACTION OF VERATRINE 437 



ter of these contractions changes rapidly with each succeed- 

 ing curve until a perfectly normal record may be secured. 

 Explain the nature of this change in the contraction curves. 

 Why are there undulations at the top of the curves ? AVhat 

 effect has fatigue on the action of the drug ? Let the muscle 

 rest a while and see if you can get a second series like the 

 first, Now take a few contraction records from the normal 

 (left) gastrocnemius muscle to compare with the curves 

 showing the drug action. 



EXPERIMENT CXLII. 

 Veratrine. (Turtle: Lung Tracing.) 



1. Arrange a turtle for recording lung tracings. Inject 

 two cubic centimeters of veratrine solution (ten cubic centi- 

 meters equal one milligram) into the ventricle and note the 

 action on the lungs. If this does not give you a record then 

 pour some of the solution over the lungs (local application). 

 Do you get a record ? If so on what structures did the drug 

 act to produce the result I (It is very advisable to remove 

 all the intestines, liver and bladder and as much as possible 

 of the skeletal muscles from the turtle before making a test 

 on the lungs, for sometimes the skeletal muscles suddenly 

 contract and obscure the results. The cord should also be 

 thoroughly pithed. One can then look at the lungs closely 

 and see if they contract.) 



EXPERIMENT CXLIII. 



Veratrine, Adrenaline. (Dog: Blood-pressure, Respiration, 



Intestinal Contraction.) 



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

 tion and intestinal contractions. The burettes contain verat- 

 rine (ten cubic centimeters equal one milligram) and 

 adrenaline (1:10,000). 



