STRUCTURE OF THE HAIR. 249 



externally of polyhedric cells superimposed upon these. These 

 cells are characterized by their large round nuclei, that stain 

 deeply with carmine, and by the sparing quantity of homo- 

 geneous protoplasm of which they are composed. Above the 

 papilla the amount of the protoplasm augments. Both the 

 cells and the nuclei are at first oblong, but at a higher level 

 become fusiform with rod-shaped nuclei. 



In this part, which usually exceeds the length of the papilla, 

 the hair root gradually diminishes in thickness, and is. still 

 bounded by the obliquely-placed scales of the cuticle. The 

 cells composing the root here also become stained with 

 carmine. 



The outlines of the individual cells cease to be visible at a 

 tolerably defined limit, fine lines appearing in their place, that 

 seem to be formed by fibrillated and elongated nuclei. The whole 

 mass no longer stains with carmine, and forms in grey hairs, 

 from which this description is taken, the stiff, silvery, and horny 

 cortical substance of the hair shaft. Thus the axile portion of 

 the hair root enclosed by the cuticle cells is continuous with 

 the substance of the hair, whilst the cells that in the first 

 instance are spheroidal the so-called hair cells become con- 

 tinuously more fusiform, and ultimately converted into thin 

 horny and spindle-shaped bodies. 



The peripheric portion of the hair root lying between the 

 cuticle cells and the vitreous layer of the hair follicle is continu- 

 ous with the cuticle of the root-sheaths and with the sheath of 

 Huxley. 



Its deeper-seated part consists of at least three layers of 

 cells, of which the most external are elongated in the direction 

 of the long axis of the hair, whilst those applied to the cuticle 

 are for the most part polygonal. 



The cells adjoining the cuticle of the hair introduce them- 

 selves between the scales of which it consists, and become con- 

 verted into the scales that form the cuticle of the root. These 

 scales overlap each other like those of the hair cuticle, with 

 this difference, that the upper cover the greater part of those 

 lying more deeply, or, in other words, the free uncovered borders 

 of the scales of the hair cuticle look upwards ; those of the 

 cuticle of the root-sheath, on the other hand, downwards. 



