294 



EXPERIMENTAL PHARMACOLOGY 



ton pass a probe (Fig. 261) and with a circular motion de- 

 stroy every part of the brain. Keep the cotton plugged 

 tightly in the opening. If it is desired to destroy the cord 

 a one-eighth inch soft brass wire slightly curved at the 

 end may l3e inserted past the cotton and forced through 

 the foramen magnum and down the spinal canal. Bend 

 the animal's neck and head a little to assist in getting the 

 rod to enter the canal easily. Remove the rod, plug the 

 opening tightly with cotton, and replace the animal's head 

 into its original position. Remove the ether quickly, the 

 animal will lie perfectly still and the blood-pressure will 



Fig. 262. After the brain (and cord, if desired) is destroyed the trephine opening 

 is plugged tightly with a wad of cotton forced in by the hooked end of an aneurism 

 needle. The animal's head is then quickly returned to the usual position. 



fall to a height of about three-fourths to one inch above 

 the base line as seen on the drum. 



If negative pressure is used change to this now. If pos- 

 itive pressure is used attach the tambour and adjust all 

 writing points on a slow drum, lung tracing at the top, 

 below this the blood-pressure, and then the base line and 

 time signal. The lung tracing should have an amplitude of 

 about three inches. Be sure the manometer pointer will 

 pass up just to the right of the tambour pointer. 



Take one-half or one inch of normal record. Inject one 

 cubic centimeter of pilocarpine. Wait a little for the ef- 

 fect to develop ivell. Then inject one-half cubic centime- 



