LESSON VII 

 MUSCLE AND NERVE (Continued) 



SPEED OF THE NERVE IMPULSE IN THE FROG AND MAN. CONDUC- 

 TION IN BOTH DIRECTIONS 



1. Histologic Study of Nerve Tissue. Examine nerve tissue under 

 the low and high powers of a microscope. Employ horizontal as well 

 as transverse sections. Identify the axis-cylinder with its fibrils, the 

 medullary sheath, neurilemma, and nodes of Ranvier. 



2. Speed of the Nerve Impulse in Cold-blooded Animals. Place 

 two pairs of needle electrodes upon the rod in the moist chamber, and 

 connect them by means of wire of medium caliber with their cor- 

 responding binding-posts inside the chamber. Attach the wires from 



FIG. 34. SPEED OF THE NERVE IMPULSE. 



M, Muscle and nerve connected with writing lever W and two pairs of electrodes 

 N and F. The wires from inductorium J are connected with the pole changer P, so that 

 the nerve may be stimulated either near to or far away from the muscle. 



the secondary coil of the inductorium to either pair of outside posts. 

 Underneath the moist chamber adjust a writing lever and electromag- 

 netic signal. The writing point of the latter should be adjusted in the 

 same ordinate as the point of the recording lever. The binding-posts 

 upon the signal are connected, on the one hand, with post 1 of the 

 inductorium and, on the other, with the simple key. From the latter 

 the wire is continued onward to the dry cell and subsequently to post 2 

 of the inductorium. Adjust the secondary coil to give induction shocks 

 of medium strength. 



Make a muscle-nerve preparation, taking care not to injure the nerve. 

 Permit the lower segment of the spinal cord to remain attached to it. 



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