ADVANCED EXPERIMENTAL PHYSIOLOGY 155 



FIG. 155. Record of the contraction of auricle and ventricle (toad) by the use of 

 Gaskell's clamp and levers. The upper tracing is the auricle and here the con! raction 

 is represented by the down-stroke. The time is marked in seconds. (L.H.) 



Fio. 166. Record of the contraction of the toad's heart by the suspension method. 

 Heat applied by the copper wire method. The signal in th third line shows the 

 period during which the sinus was heated. Acceleration of the whole heart was pro- 

 duced. In this curve the down-stroke represents the contraction. The time is 

 marked in seconds. (L.H.) 



