convexity of the one beneath, which is
placed transversely with reference to the former, and so is effectually
hindered from getting any farther. And this I have frequently
experienced in my dissections of veins. If I attempted to pass a probe
from the trunk of the veins into one of the smaller branches, whatever
care I took I found it impossible to introduce it far any way by reason
of the valves; whilst, on the contrary, it was most easy to push it
along in the opposite direction, from without inwards, or from the
branches towards the trunks and roots.

And now I may be allowed to give in brief my view of the circulation of
the blood, and to propose it for general adoption.

_The Conclusion_

Since all things, both argument and ocular demonstration, show that the
blood passes through the lungs and heart by the action of the
ventricles; and is sent for distribution to all parts of the body, where
it makes its way into the veins and pores of the flesh; and then flows
by the veins from the circumference on every side to the centre, from
the lesser to the greater veins; and is by them finally discharged into
the _vena cava_ and right auricle of the heart, and this in such a
quantity or in such a flux and reflux, thither by the arteries, hither
by the veins, as cannot possibly be supplied by the ingesta, and is much
greater than can be required for mere purposes of nutrition; therefore,
it is absolutely necessary to conclude that the blood in the animal body
is impelled in a circle and is in a state of ceaseless motion; and that
this is the act, or function, which the heart performs by means of its
pulse, and that it is the sole and only end of the motion and
contraction of the heart. For it would be very difficult to explain in
any other way to what purpose all is constructed and arranged as we have
seen it to be.

SIR JOHN HERSCHEL

Outlines of Astronomy

Sir John Frederick William Herschel, only child--and, as an
astronomer, almost the only rival--of Sir William Herschel, was
born at Slough, in Ireland, on March 7, 1792. At first privately
educated, in 1813 he graduated from St. John's College, Cambridge,
as senior wrangler and first Smith's prizeman. He chose the law as
his profession; but in 1816 reported that, under his father's
direction, he was going "to take up stargazing." He then began a
re-examination of his father's double stars. In 1825 he wrote that