1912.] 



" Narcosis Progression " in Mammals. 



145 



first beat then synchronises at a certain point with the point of commence- 

 ment of a beat at the second— and so on. 



Increase in the rate of rhythm is then accompanied by a disappearance of 



Fig. 1. — Experiment C, XXXIV, record 60; 11.4.11. — Normal cat, record of narcosis 

 progression obtained by registration of the movements at the ankles of the intact 

 hind limbs. 



The movements are here slow. It will be observed that there are distinct pauses 

 in flexion relaxation between the beats, and that there are slight pauses at the top of 

 the beats. The pauses in relaxation are of greater duration than are the beats. 

 The beats are alternate in the two hind limbs. The corresponding ordinates marked 

 1, 2, 3, 4 demonstrate that the commencement of a beat at the left ankle occurs after 

 the commencement of a pause between beats at the right, and that the termination 

 of that beat occurs before the termination of the same pause. Thus, for instance, 

 immediately after ordinates 4 both limbs for a short time are in flexion relaxation. 



In this and in all the other figures, except figs. 7 and 8, the upper tracing is that 

 obtained from the movements of the right foot and the lower that from the left. 

 The rise of the curve denotes flexion, and the fall extension at the ankle. Corre- 

 sponding ordinates on the two tracings (usually numbered 1, 2, 3, etc.) demonstrate 

 the time relations of different points. A millimetre scale has been drawn before 

 the record was varnished, and is thus reduced in proportion with the rest of the 

 record. The lowest line registers time in seconds. 



the pause between the beats of either foot. At each ankle the commence- 

 ment of a beat follows immediately upon the termination of the preceding 



