ONG GEE CrRCULATION THROUGH IT 185 
ally red tint than the right, a difference which gradually passed off, so that, 
in the course of one minute and three-quarters, the hands were again of equal 
colour. Two minutes later, I repeated the experiment, and this time kept the 
left hand raised for two minutes, and then, on lowering it, found it to become in 
ten seconds much redder than the other, which had been suspended the whole 
time ; and, just as might have been expected after the more protracted action 
of the nervous apparatus, the repose was longer in duration, so that, even after 
two minutes and twenty seconds, when I was obliged to start for the train, 
the left hand was still shghtly the redder of the two. Now such a result as this 
was entirely contrary to what could be explained as a consequence of mere 
hydrostatic laws. If the arteries had been simply emptied in the elevated 
position by the force of gravity, all that could have resulted on restoring the limb 
to the dependent posture would have been a return more or less rapidly to 
the previous condition of vascular fullness. And it is an interesting fact that 
the veins, though comparatively thin-walled, and much more readily distensible 
than the arteries, do not at once recover their former size when the elevated 
limb is lowered, but remain for a while markedly less turgid than those of the 
other hand, even when, through arterial dilatation the colour of the skin is not 
only more florid but manifestly darker. Hence this apparently trivial experi- 
ment, if duly considered, seems to me of itself sufficient to prove the truth of 
the doctrine for which I am contending. 
