164 



ADVANCED LESSONS IN PRACTICAL PHYSIOLOGY 



Stop bleeding by tampons, torsion, and ligation of the blood-vessels. 

 Expose the laminae of several adjoining vertebras. Cut through them 

 and remove the dorsal wall of the spinal canal of this region. Take care 

 not to injure the spinal nerves. 



Incise the dura mater. Expose the spinal cord and identify the 

 anterior and posterior roots of one of the spinal nerves. Isolate these 

 roots and place each in a loose ligature. Stimulate each with a weak 

 tetanizing current. Eventually tie these ligatures, the one upon the 

 anterior root close to the cord, and the one upon the posterior root far 



FIG. 97. DIAGRAM SHOWING THE MOTOR 

 POINTS IN THE CEREBRUM OF THE DOG. 



FIG. 98. THE MEMBRANES OF THE SPINAL 



CORD. 



1, Dura mater; 2, arachnoid; 3, pos- 

 terior root of spinal nerve; 4, anterior root 

 of spinal nerve; 5, ligamentum dentatum; 

 6, linea splendens. (After Ellis.) 



away from the cord. Stimulate the distal end of the former with a 

 weak tetanizing current. Repeat the stimulation upon the central end 

 of the latter. Tabulate the results, and determine the direction of 

 conduction in each root. 



Kill the animal by an overdose of ether. Remove a segment of the 

 spinal cord, noting the size and shape of the subdural space, and the 

 manner in which the spinal nerves are enveloped by dura. 



Remove the brain. Identify its different parts, and especially those 

 to which attention has been called in the lectures. 



