9 8 



Scientific Proceedings (49). 



for five-day periods for comparison with the controls of the same 

 periods, and all experiments were continued for at least ten days. 



The results show that amino acids and their derivatives have 

 but slight effect on the division rate at any period of vitality. The 

 purins and their derivatives have but a slight effect on the division 

 rate when vitality is very low or very high, but a marked effect of 

 increasing the rate when vitality is decreasing (allantoin) or 

 increasing (hypoxanthin, xanthin). 



71 (680) 



The first onflow and diastolic waves in the venous pulse. 



By E. M. EWING. 



[From the Department of Physiology of the University and Bellevue 

 Hospital Medical College.] 



Simultaneous records of the contractions of the auricle and 

 ventricle, intraventricular pressure, arterial pulse, and the pulse 

 of the superior vena cava were made. 



Previous investigators have not agreed as to the time relations 

 of the 3d positive (Mackenzie's "v") wave, some placing its 

 appearance during ventricular systole, and others believing that it 

 occurs in diastole. This confusion has arisen from the fact that 

 Mackenzie's "v" wave in reality consists of two positive waves 

 which are separate both in time and origin. (Bard described two 

 such waves, but was not definite concerning the time relations.) 



The first of these waves has been called the "onflow" wave, and 

 the second, the "diastolic" wave. They are preceded, of course, 

 by the auricular and systolic ("c") waves. 



In a series of some fifty dogs, the onflow wave has always 

 appeared just at the end of auricular relaxation, and therefore, 

 during the first half of ventricular systole. The wave is terminated 

 at the very beginning of ventricular diastole. The origin of the 

 wave cannot be ascribed to the passive auricle, nor to the ventricle, 

 the base of which is still moving downward, and which would 

 tend, therefore, to produce a negative, rather than a positive 

 wave. The wave must simply represent the increased pressure 



