EFFECT OF LIGATURE 303 



a cut or a ligature to the petiolule of the leaflet, about 3 mm. 

 below the pulsating pulvinule, to find the various peculiarities 

 recorded of the action of the heart repeated here, with 

 striking similarity. 



The most convenient way to apply what was equivalent 

 to the ligature, was to hold the petiolule in a very small 

 clamp and proceed to record the normal pulsation. After 

 doing this for some time, the clamp was suddenly tightened. 



Fig. 148. — Effect of ligature in inducing an arrest of pulsation 

 of Desmodium at diastole. 



This induced an arrest of pulsation, either at once or after 

 one or two vigorous beats. Similar effects were also obtained 

 by making a cut, after suitably supporting the leaflet. 

 These results depend somewhat on the condition of the 

 specimen. It is generally found that the nearer it is made to 

 the pulvinule the more effective is the cut or ligature in 

 inducing the arrest. 



In fig. 148 is seen the arrest induced by ligature : it is 

 very remarkable that here, as in the case of the pulsating 

 heart, the arrest by ligature took place at diastole. 



In fig. 149 is seen the arrest induced by a cut. While 

 the leaflet is still in the condition of arrest it is often possible 

 to renew the pulsation by an induction-shock. These 



