BALDNESS. Absence of hair upon the scalp, or loss of hair already grown. The term a/opecia is often used synonymously with the term baldness, but strictly speaking should not he applied to lack of hair that is congenital. Entire absence of development of the hair is termed congenital baldness, or hypotriehosis congeģita. Senile baldness is termed ealvities or calpitium. Pincus is authority for the state ment that the life of a hair is from two to six years, 'at the end of which time it falls and is replaced by new growth. According to this calculation, from 50 to 60 hairs are shed each day. During vigorous health and until the prime of life has been passed, enough new hairs grow to replace the dead ones. and baldness does not occur. Baldness occurring at 40 or 50 years of age is called premature alopecia, and is due to disease. A frequent cause of baldness in the young is seborrhceic eczema of the scalp, which is characterized by increased formation of dand ruff. and is of bacterial origin. It occurs as early as the eighteenth year. In the absence of this cause, baldness in young men has been ascribed to the effects of the lead used in pre paring the 'sweat-leather' which lines the hat where it touches the head. Anemia, wasting
diseases, such as fevers, child-bearing, and de bility due to dissipation, are all ascribed as causes of baldness. It is also hereditary in cer tain families, and in such cases appears to be due to failure in the nutrition of the sealp. Wo men are less liable to baldness than mena fact probably due to the circumstance that they take better care of the hair, wet it less often, and less frequently exhaust the natural oil of the seba ceous glands of the scalp by the use of strong alkaline shampoos. Syphilis and favus (q.v.) cause baldness in both sexes. Shaving the head, when the hair falls in great quantity, was wive thought of advantage: but the wearing of a wig impedes the growth of the hair upon a shaven scalp. Chloral. ointment of mercury, cantharides, sulphur, tar, and resorein, are used with success in checking baldness in some cases. Consult: Kaposi, Diseases of the Skin (Eng. trans., New York, 1895) ; Unna, in Archiv fiir Dermatologie and Syphilis (1882).