XLIV.] 



MYOGRAPHIC EXPERIMENTS ON MAN. 



229 



attached just above the attachment of the latter, and the tibia below the knee- 

 joint. Pass a fine metallic hook tlirough the knee-joint or its ligaments, and 

 attach it to the projecting hoolc of fine wire fixed to the short arm of the lever. 

 Fix the tendo Achillis to a hook connected with the wire passing through the 

 cork in the neck of the glass cylinder. 



Fio. 152:— Wild's Apparatus for Studying the Action of Poisons on Muscle. 

 P. Platform ; S. Stand : al. After-load : L. Lever ; B. Bottle with muscle 



D. Drum; 

 K. Key. 



{h.) Fill the glass cylinder— which encloses the muscle — not quite full with 

 normal saline. Stimulate the muscle directly with a break shock, using a 

 mercury key in the primary circuit, and take a tracing. 



('•.) Remove the normal saline with a pipette, and replace it with a solution 

 of the drug whose action you wish to study, e.g., veratria 1 in 5000, or barium 

 chloride i in 1000. Study the veratria tracing (fig. 137). 



5. Interference -Phenomenon in Nerve-Muscle Preparation. — Arrange a 

 nerve-muscle preparation in a moist chamber, and weight the recording lever 

 with 20 grams. Place the central end of the nerve over platinum electrodes, 

 and allow a portion of the nerve nearer the muscle to hang in the form of 

 a loop in contact with strong glycerin, when the muscle becomes tetanic. 

 When tetanus occurs throw in an interrupted current, when the tetanus is 

 diminished. Is this interference-phenomenon an inhibitory one I (Kaiser, 

 Zeitsch.f. Biol. J 1891, p. 417.) 



LESSON XLIV. 



MYOGRAPHIC EXPERIMENTS ON MAN— 

 ERGOGRAPH AND DYNAMOGRAPH. 



1. Myographic Experiments on Man. 



Fick lias devised a simple apparatus for this purpose, using 

 isometric curves. The muscle investigated is the A I/duct or indicts 

 or interosseus doi\salis primus of the hand. It arises by two heads 

 from the adjacent surfaces of the metacarpal bones of the thumb and 

 index-finger, and is inserted into the dorsal aponeurosis of the latter. 



