However, a little careful checking up will eliminate most of the possible mistakes and enable us to obtain information of the greatest value from color. For instance, if our patient be of Southern blood, or tanned from the seashore, the good red blood in his arteries is pretty safe to show through at the normal blush area on the cheeks; or, failing that, through the translucent epithelium of the lips and gums. If, on the other hand, this yellow tint be due to the escape of broken-down blood-pigments into the tissues, or a damming up of the bile, and a similar escape of its coloring matter, as in jaundice, then we turn to the whites of the eyes, and if a similar, but more delicate, yellowish tint confronts us there, we know we have to deal with a severe form of anaemia or jaundice, according to the tint. In extreme cases of the latter, the mucous membrane of the lips and of the gums will even show a distinctly yellowish hue. The frightful color of yellow fever, and the yellow "death mask," which appears just before the end of several fatal forms of blood poisoning, is due to the tremendous breaking down of the red cells of the blood under the attack of the fever toxins, and their leaking out into the tissues. A similar process of a milder and less serious extent occurs in those temporary anaemias of young girls, known for centuries past in the vernacular as "the green sickness." And a delicate lemon tint of this same origin, accompanied by a waxy pallor, is significant of the deadly, pernicious anaemia and the later stages of cancer. The most significant single thing about the red flush, supposed to be indicative of health, is its location. If this be the normal "blush area," about the middle of each cheek,--which is one of nature's sexual ornaments, placed, like a good advertisement, where it will attract most attention and add most beauty to the countenance,--and it fades off gradually at the edges into the clear whiteness or brownness of the healthy skin, it is probably both healthy and genuine. If the work of either fever or of art, it will generally reveal itself as a base imitation. In eight cases out of ten of fever, the flush, instead of being confined to this definite area, extends all over the face, even up to the roots of the hair. The eyes, instead of being clear and bright, are congested and heavy-lidded; and if with these you have an increased rapidity of respiration, and a general air of discomfort and unrest, you are fairly safe in making a diagnosis of fever. If the first touch of the tips of the fingers on the wrist shows a hot skin and a rapid pulse, the diagnosis is almost as certain as with the thermometer.