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.
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.
"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.