STUDIES ON HAIR, WITH SPECIAL REFERENCE TO HYPERTRICHOSIS

Abstract

VIII. GENERAL ASPECTS OF THE HAIR PROBLEM A cursory survey of available information on the pilary system suffices to show that our knowledge of hair is deficient in many respects. Even in its anatomy and embryology there are a number of points that have not been cleared up. There is nothing but speculation concerning the phylogeny of hair. Its comparative anatomy in the mammals is better understood, although even here there are important problems that remain to be solved. Racial differences in hair have been much studied, and there is a considerable volume of literature relating to this phase of the subject, but much of it is of a superficial character with little real value. The weakest place in the whole field, with the possible exception of questions of phylogeny, is in the understanding of the factors regulating growth, either normal or abnormal. It is scarcely an exaggeration to say