ADVANCED EXPERIMENTAL PHYSIOLOGY 93 



hyoglossus preparation used in the previous experiment. Five 

 minims of the vera trine solution are injected into the lymph sac 

 in which the muscle lies. The drum is arranged to revolve at a 

 slow rate of about 2 cm. in 10 sees., and a simple key instead of 

 the " striker " of the drum is placed in the primary circuit. After 



FIG. 95. Comparison of contractions of red and white muscle of rabbit, 

 stimulated indirectly. 



Upper curve is response of the red soleus and lower curve that of the white gastrocnemius. Time 

 marker, 50 per sec. The tracing to be read from right to left. (M.S.P.) 



waiting a few minutes the muscle is stimulated by a single maximal 

 induction- shock, and its contraction recorded. The curve shows 

 that the response is a single slow contraction with an enormously 

 prolonged relaxation. 



Replace the hyoglossus by the gastrocnemius and sciatic prepara- 



FIG. 96. Contraction of the hyoglossus muscle. 

 Time marker, 100 per second. (A.P.B.) 



tion and stimulate it in the same way. As soon as the first con- 

 traction is over, the muscle is stimulated again, and so on for half 

 a dozen contractions. It will be seen that the first contraction 

 (Fig. 97) consists of a smart initial twitch followed by a much longer 

 contraction, and an even more prolonged relaxation. The second 

 contraction shows the same characters to a less extent, and the 



