112 
Scientific Proceedings (43). 
or completely stripped to the waist, under the ordinary conditions 
of room temperature, usually lay between 2 and 5 cc of blood 
flow per 100 cc of arm substance per minute. More recently, 
by a calorimeter method, G. N. Stewart has obtained rates in 
the hand approximately 10 cc. of blood flow per 100 cc. of hand 
substance per minute. We have attempted to compare the two 
methods because it seemed improbable to us that this discrepancy 
could depend entirely upon variations in external conditions, 
such as the room temperatures or the amounts of clothing worn. 
The plethysmograph method was applied to the hand and the 
results compared with those obtained by the calorimeter method 
on the hand and with those obtained when the plethysmograph 
included the forearm and the lower arm. Our method does not 
give very satisfactory results for the hand. The curves are apt 
to rise abruptly when the pressure is applied and the rate of swell- 
ing remains constant but a short time before it lessens, owing 
apparently to the small venous capacity of the hand. 
It is nearly always possible, however, to obtain curves where 
the rate of inflow is nearly constant for 2 cc. or more. By selecting 
such parts of the tracings, an approximate rate of flow in the hand 
was obtained. 
Table L 
Co. 
Ca. 
So. 
Average 
Room 
Temp. 
Average 
Calorimeter 
Temp. 
Rate by 
Calorimeter. 
Plethysmograph Plate. 
Remarks. 
Hand. 
ist Arm. 
2d Arm. 
24° 
23° 
27.5 0 
25-7° 
29.8 0 
29.O 0 
3-1 
4.8 
10. 0 
4.8 
7.8 
10.2 
2.9 
2.3 
4.5 
3- 1 
2.4 
4- 5 
Thick skin, hand 
cold. 
Hand cool. 
Hand warm. 
In the experiments charted in Table I. the individuals were 
stripped to the waist. The rate of flow in the hand was first 
determined by Stewart's method. After this the hand was dried 
and successive determinations of the blood flow, by the plethys- 
mograph, were made on the forearm, the hand, and again on the 
forearm. A glance at this table indicates that the blood flow 
in the hand was relatively faster than it was in the combined hand, 
forearm, and lower arm; and, furthermore, that the plethysmo- 
graph method, when applied to the hand, gave somewhat faster 
rates of flow than did the calorimeter method. In these experi- 
ments the plethysmograph contained air only. 
