ACTION ON BLOOD-PRESSURE IN THE FROG. 501 



the body, and a solution of casca is injected beneath the skin, 

 the heart's action is slowed, and is eventually stopped in sys- 

 tole ; previous to its stopping, however, pouch-like dilatations 

 are formed ; in this respect the action of casca is similar to 

 that of digitalis and other cardiac poisons. 



Experiment XXXL— April 27. 



A cat was chloroformed ; a cannula placed in the left jugular 

 vein and one in the trachea. Artificial respiration was com- 

 menced, and the thorax was opened. The heart was beating 

 regularly, but it was difficult to count the pulsations. They 

 were counted by one person as 90, by another as 180. 



Ten c.c. of a saturated watery solution of watery extract of 

 casca were injected into the jugular vein. 'No apparent effect 

 was produced. 



Seven c.c. more were injected in the course of a few minutes. 

 "Within about a minute of the last injection the ventricle no 

 longer contracted as a whole, but became pouched, the upper 

 half seeming to overlap the under half so as to produce a trans- 

 verse fold. 



A few seconds afterwards, the lungs, w^hich had hitherto been 

 rosy, became white, and almost immediately the motions of all 

 cavities of the heart completely ceased. On irritation of the 

 ventricle no movement occurred. 



Both vagi were divided, but without effect on the neart. 



It was noticed that the rosy colour of the lungs returned, 

 although the heart did not again beat. No pulsations were 

 noticed in the pulmonary vessels. The heart was perfectly 

 firm, and seemed to be in systole ; but on tying a ligature 

 round the base so as to include the large vessels, it contracted 

 to about one-third of its former size. 



The action of casca on the mrammalian heart is seen from this 

 experiment to be similar to its action on the heart of the frog. 



Experiment XXXII. 

 Action on Blood-pressure in the Frog. 

 The cerebrum of a large frog was destroyed. A cannula was 

 then inserted into the left aorta, and was connected wdth a 



