Structure, and Life of the Human Hair. 171 



it, nor is it eA'en so dark as the developed hair ; the cells are, 

 it is true there, but considerably contracted, therefore smaller, 

 while they are not pressed so closely together, but are arranged 

 in rows by the more or less long uniting threads. The ci/to- 

 blastema here is also light coloured. In the third part of the 

 pulp, however, where the cells appear much as they do in the 

 second, a darker colour is at once perceptible, and it depends 

 upon the coloration of the firmer and more tenacious interme- 

 diate substance which unites the fibres. This is very easily 

 ascertained after treatment of the developed hair with muria- 

 tic acid, when, between the finest fibres, that yellowish or 

 brownish uniting mass, the cijtohlastema, distinctly makes its 

 appearance, and is undoubtedly the chief cause of the colour 

 of the hair. I have unfortunately not yet been able to examine 

 how hair of other colours, such as light blonde and white, are 

 circumstanced in this respect ; for hitherto I have only em- 

 ployed brown and black. When these are treated with muriatic 

 acid they commimicate a portion of their colouring matter to 

 the liquid, which thus acquires a dark greenish tint, while the 

 hair itself becomes paler. This, at least, partial extractability 

 of the colouring matter, harmonizes extremely well with the 

 view that its chief seat is in the surrounding cytohlastema, and 

 is in this way quite explicable. I have not yet made -any ob- 

 servations as to how the hair-fibres are circumstanced in hairs 

 which are thinner at their roots than in their subsequent course, 

 as, for example, in the eyebrows. 



According to the investigations of Henle and Schwann on 

 the changes of the cells going forward in other horny textures, 

 and according to the result that these conversions must be 

 derived from a self-acting power in the cells, the same must 

 at once be supposed regarding the hair, and the opinion must 

 be rejected that all changes of the hair have reference to the 

 matrix alone. The idea of the dead or lifeless structure within 

 the boundaries of the organism, must now be given up. The 

 observations communicated on the origin of the hair afford the 

 confirmation of the supposition made above. It cannot, how- 

 ever, be without interest to obtain from pathology new proofs 

 of the life existing in the hair itself. A residence of some 



