370 



Messrs. Parkes and Wollowicz on the Effect of [May 19, 



tracings, as will be seen on comparing the 10 p.m. curves of the first period 

 with that of the ninth day. The larger quantities of alcohol produced, 

 however, greater effects, and the tracings of the twelfth, thirteenth, and 

 fourteenth days are very striking. They show, of course, a greatly in- 

 creased rapidity of beat. The first event (to use Dr. Burdon-Sanderson's 

 terms), or systolic wave, is better marked ; the ascent of the lever is more 

 vertical, and is greater in amount ; the summit is sometimes sharp, but in 

 most cases rounded. The second event, or arterial pressure, is not appa- 

 rently so much altered, and in most cases probably is not changed. The 

 third event, or disastolic collapse, is more rapid than before alcohol ; there 

 is very little evidence of the fourth event, or diastolic expansion. 



The interpretation is that there is increased frequency of the ventricular 

 contractions, and increased rapidity of each contraction ; the ventricle 

 therefore is doing more work in a given time, the period of rest for the 

 heart is much shortened, the blood moves more freely than usual through 

 the capillaries, so that the increased quantity of blood which it is to be 

 presumed is thrown into the arteries, is very quickly got rid of. 



SPHYGMOGRAPHIC TRACINGS. 

 Right Radial Artery. 

 First Period. — 8 days Water-drinking. 



Second Day. 



Third Day. 



