199 
of Edinburgh, Session 1869 - 70 . 
Two tubes were used in these experiments. The length was 56 
inches. The first (Tube C) had a diameter of T259 of a millimetre. 
The second (Tube A) had a diameter of 09289 of a millimetre. 
Table IY. 
No. of 
Experi- 
ments. 
Fluid used. 
Diameter 
of Tube. 
Length 
of Tube. 
Tempera- 
ture. 
Pressure. 
Time of 
Flow of 
100 Cubic 
Cents 
in Seconds. 
43 
Water, 
Tube C. 
mm. 
1-259 
mm. 
914- 
15°' C 
mm. 
601-7 
42-10 
44 
Water, 
,, 
,, 
39°-5 C 
,, 
39-43 
45, 46 
Venous blood of calf, 
,, 
,, 
0° 
OO 
CO 
589-0 
54-9 
46, 47 
Venous blood of ) 
calf, defibrinated > 
and arterial, . ) 
” 
” 
” 
” 
53-11 
48, 49 
Arterial blood of calf, 
” 
” 
” 
” 
60-07 
50 
Water, 
Tube A. 
0.9289 
914- 
38° -5 
601-7 
69-4 
15-53 
Arterial blood of calf, 
” 
” 
” 
” 
160-1 
From this experiment it would appear that the rate of flow of 
blood just drawn from the vessels of a living animal is very much 
greater than the rate of flow of blood which, having been defibri- 
nated, has been allowed to stand for some time, as was the case in 
experiment 40. In defibrinated blood the corpuscles tend un- 
doubtedly to run together, and the masses thus formed by their 
coherence must necessarily account for the extreme slowness. The 
pure and perfectly warm blood flowed, indeed, more rapidly than 
did the serum obtained from ox-blood, which had been used in a 
previous experiment. In experiments 36, 37, 38, and 39, it was 
found that the time of flow of equal quantities of serum and water 
were represented by the ratio of 1*4:1. In experiments 43-49, 
it was found, on the other hand, that the rate of flow of equal 
quantities of pure blood and water were represented by the ratio of 
1-3:1. 
In a former part of this paper we stated that the diameters of 
the tubes used by us differed from those of Poiseuille in being 
much wider. 
