Leukonychia

T HE white spots that so frequently occur on the nails, especially in young women, have a number of names, many of them frivolous, such as "kisses," "wishes," or "gift spots." Like most strange happenings they have their folklore also, and in Bavaria, according to Heller,2-3 it is believed that the person having them shall live as many years as there are spots on the nails, while on the Rhine the person having them is held to be a liar. That the names should be frivolous is often quite fitting, as frequently the spots are of trifling importance. This, however, is far from saying that they are of no account whatever, as .nothing pertaining to the human being is that, and, furthermore, this symptom, under certain circumstances, may have a grave significance. Jonathan Hutchinson once aptly said: "It is convenient to think of a nail as a gigantic flattened hair." The nail plate corresponds to the hair, the slot out of which it springs to the hair follicle, and the matrix from which the nail grows is analogous to the hair papilla. The matrix, as being an organ of growth, is composed of very soft cells, and in these cells there are scattered minute particles of air, ordinarily invisible. When, however, the root of the nail is rudely pressed upon, as is often the case in pressing back the posterior nail-fold in manicuring, the injury causes the cells to imbibe an unusual quantity of air, so forming the white spots and stripes. That these spots are air can be demonstrated by darkfield illumination of sections of the nail in which the air-filled spaces show white against the darker, normally dense nail substance.' Also, if the surfate of the nail, which in leukonychia is smooth, is cleared off with a file one finds that the white spot is composed of cells which are crumbly, soft and infiltrated with minute air bubbles which, by refraction, give the white cloudy appearance. This cloudiness is often marked, and Sabouraud compares it to the stratified clouds seen in the sky on a summer evening. Heidingsfeld of Cincinnati, therefore, was perfectly correct in stressing this kind of injury in the production of this symptom, and it accounts for its frequent occurrence in young girls who are so interested in nails as ornaments. Leukonychia of the nails of the toes is not nearly so frequently observed as of the fingers. They, of course, are not so exposed to view, and they are also not so exposed to the peculiar kind of injury incident to manicuring. The injury of manicuring is directly over the lunula, and therefore directly over the matrix where, as was said before, leukonychia arises. There are other, more important causes than local injury for the production of both transverse fturrows