The reason why : $b a careful collection of many hundreds of reasons for things which, though generally believed, are imperfectly understood. A book of condensed scientific knowledge for the million — John Stuart Mill — John Shaqi
The reason why : $b a careful collection of many hundreds of reasons for things which, though generally believed, are imperfectly understood. A book of condensed scientific knowledge for the million
John Stuart Mill · en
Because they give _firmness to the touch_, and enable us to apply the
extremities of the fingers to many useful purposes for which they
would otherwise be unfitted. They enable us to _press the tips of the
fingers_, where the highest degree of sensitiveness prevails, so as
to bring _the largest amount of nervous perception_ into the sense of
touch.
909. _Why do white spots occur upon the nails?_
Because the vascular surface underneath is attached to the horny
texture of the nail; but by knocks and other causes, the nail sometimes
_separates in small patches from the membrane_ below, and becomes _dry
and opaque_.
910. _Why is there a circular line of whitish colour at the root of the
nail?_
Because there the nail is _newly formed_ by the vascular substance
out of which it grows, and has not yet assumed its proper horny and
transparent nature.
911. _Why is the eyeball white?_
Because the blood-vessels that supply its surface are so very fine that
they do not admit the _red corpuscles_ of the blood.
912. _Why does the eyeball sometimes become blood-shot?_
Because, under exciting causes of inflammation, the _blood-vessels
become distended_, and the red corpuscles enter, producing a net-work
of red blood-vessels across the white surface of the eye.
913. _Why are the lips red?_
Because the lips are formed of the _mucous membrane_ that lines the
body internally, and covers the surface of most of the internal parts.
This membrane contains a great number of minute red vessels, which give
softness and moisture to the surface. A very beautiful illustration
of the softness, moisture, and delicate colour of the mucous membrane
is afforded by turning up and examining the under surface of the upper
eyelid.
[Verse: "Hast thou not known, hast thou not heard, that the
everlasting God, the Lord, the Creator of the ends of the earth,
fainteth not, neither is weary? there is no searching of his
understanding"--ISAIAH XL.]
914. _Why do delicate persons look pale and languid?_
Because, generally from the want of exercise and fresh air, their blood
is deficient of the healthy proportion of _red corpuscles_.
915. _Why does exercise and fresh air impart to healthy persons a red
and fresh appearance?_
Because the redness of the blood is due to the _amount of oxygen_ which
it contains, and air and exercise _oxygenise_ the blood, and diffuse it
throughout the system.
916. _How is the blood propelled through the arteries?_
By the very powerful contraction (and alternate dilation) of the thick
_muscles of the heart_, assisted also by the _muscular cords of the
blood-vessels_ themselves, and in many instances by the _compression of
the muscles_ in which the arteries lie embedded.
917. _Why are the capillary arteries capable of receiving the great
quantity of blood sent out through the larger vessels?_