210 Gencral Notes. | Februar 
height. For a perfectly healthy man, the curve which they git _ 
shows that for the first hour the slumber is very light; after om 
hour and and fifteen minutes, the depth of sleep increases rapidly, 
and reaches its maximum point at one hour and forty-five minutesi 
the curve then falls quickly to about two hours and fifteen minutes 
and afterwards more gradually. At about four hours and thirty 
minutes, there is a second small rise which reaches its maxımu 
at five hours and thirty minutes, alter which the curve agat 
gradually approaches the base line until the time of awakening 
xperiments made upon persons not perfectly healthy, or afte | 
ene made some exertion, gave curves of a different form= 
cience. i 
_ EXPERIMENTS UPON THE HEART OF THE DoG WITH RE be 
VENTRICLE IN A SINGLE BEAT, AND THE INFLUENCE OF 
IN VENOUS PRESSURE, ARTERIAL PRESSURE, AND Fu and 
UPON THE WorK DONE BY THE Heart. By W.H. Hows 
F. Donaldson, Jr.\—Owing to the indirectness of the meth a 
hitherto used for estimating the quantity of blood pumped J 
from the left ventricle at each systole, this important actors 
calculations of the work done by the heart has never = frot 
factorily determined. Volkmann, and afterwards Vieron ae 
calculations based upon the mean velocity of the stream of bm 
in the unbranched aorta, obtained the fraction ao as rept systole 
and the body-weight. Fick, from data obtained by oe 
In our investigation we have made use of the dog's eee e 
pletely isolated from all other organs of the body, Wir" farit 
ception of the lungs, after the method devised by P rofessor sf 
Ce eee 
With regard to the maximum quantity of blood he waned 
thrown out from the left ventricle at a single systole a met 
result of the experiments may be stated as follows: ° wig 
to HF 
ich 
body weight is 3, or .oo17. In one exper iment 10 ge rate 
pulse-rate was 126 per minute, about the norma ‘ne norm 
obtained was h or .oo14. / In applying these results pee z 
dog, we believe that the average quantity of blood P is appro” l 
from the left ventricle at each systole in the living dog, maxi 
mated most closely in the experiments given by the 
outflow obtained from the isolated heart. ‘ims. of me 
Variations of arterial pressure, from 58 to 147 ™ No 
1383p set reprinted from the Proceedings of the Royal Society — 
