P HARM A CO LOG Y. 297 



spinal canal by inserting smaller blade of strong scissors into spinal canal 

 and cutting, taking care not to injure cord. Allow a drop of the concen- 

 trated solution of strychnin to fall directly upon cord; or with fine 

 hypodermic needle inserted 1.5 cm into the arachnoid space inject two 

 drops of the solution. 



(a) What effect has ligation of the aortae on the cir- 

 culation ? 



() Would stoppage of the circulation prevent the 

 drug from reaching the peripheral terminations or 

 trunks of the sensory nerves? Motor nerves? Muscles? 



(/) Where then, must strychnin act to produce the 

 observed symptoms ? 



(//) Would cessation of the circulation delay the ac- 

 tion of strychnin on the cord by slowing the rate of 

 its absorption by the latter ? 



(5) After observing results in experiment (4), destroy 

 first the upper then the lower portion of the cord, by 

 passing a wire down the spinal canal. 



(a) How does destruction of the upper part of the 

 cord affect the convulsions ? 



(b) What is the result of the destruction of the en- 

 tire cord ? 



(r) Do the results agree with those of previous ex- 

 periments ? 



NOTE : Destruction of the upper part of the cord 

 during the preparation of the animal may take 

 place; if so, the upper limbs will not take part in 

 the convulsions. 



(6) Further observations and comparisons. 



(a) Compare the general effects of strychnin and 

 curare in the dog. 



(3) Compare results obtained in experiments consist- 

 ing of ligating the thigh of a frog except the sciatic 

 nerve, and injecting, in the ono case strychnin, in 

 the other curare. 



