LXVIII. Veratrin. 



/. Material. Sulphate of veratrin; 1 dog; 3 frogs. 



2. Preparation. 



Prepare a solution of veratrin, 50mgrms, to 10 c.c. Pith 

 frogs. Restrain dog, but do not fasten to board. Set 

 up myograph and induction coil, the latter arranged 

 for single induction shocks. 



3. Experiments and Observations. 



(1) Give a subcutaneous injection of 15 mgrm. veratrin 

 to the dog. 



(a) Describe symptoms as they arise. 

 () Summarize. 



(2) Place thread around the sacral plexus of the pithed 

 frog so as to easily find it, as described under 

 strychnin. Inject 0.003 gms. veratrin into dorsal lymph 

 space. 



(#) Describe symptoms referable to rexflexes. 



() Note particularly the difference between a forcible 



contraction and a prolonged contraction. 

 (3) ( Sever the sacral plexus around which the thread 

 has been passed. 

 (#) How do the contractions of the legs in response 



to direct stimuli compare ? 



() Has severing the sacral plexus altered the dura- 

 tion of the contraction of the muscles supplied ? 

 (V) If veratrin still produces its typical effects, to 



what elements in the reflex arc have you limited its 



action ? 

 (d) Compare the effect of severing the sacral plexus 



in a frog poisoned with veratrin with that in a frog 



poisoned with strychnin. 



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