XLIV.] 



MYOGKAPHIC EXPERIMENTS ON MAN. 



229 



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

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

 attach it to the projecting hook 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. 



FIG. 152. Wild's Apparatus for Studying the Action of Poisons on Muscle. D. Drum ; 

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



(b.) 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 i 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? (Kaiser, 

 Zeitsch.f. BioL, 1891, p. 417.) 



LESSON XLIY. 



MYOGRAPHIC EXPERIMENTS ON MAN 

 ERGOGRAPH AND DYNAMOGRAPH. 



1. Myographic Experiments on Man. 



Tick lias devised a simple apparatus for this purpose, using 

 isometric curves. The muscle investigated is the Abductor indicis 

 or interosseus Jorsalis primus of the hand. It arises hy 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. 



