170 Dr Bidder's Bemarks on the Origin, 



comes from beneath to fall on the object sometimes from the 

 one side and sometimes from the other, the one outline seems 

 permanent, but the other sometimes to the left, sometimes to 

 tlie right, and is therefore merely a shadow. The permanently 

 remaining line is the elementary hair-fibre. In it the walls 

 eeem to lie so near, both to the primary cells and to their con- 

 tinuations, that the cellular aperture disappears from view. 

 The same is the case with the pigment-cells with which the 

 hair-cells can be most readily compared ; for the so-called 

 pigment ramifications proceeding from them are frequently so 

 fine that they elude all measurement. If the thickness of a 

 human hair of the head be estimated on an average at one- 

 tenth of a line, then, to produce its diameter, .there must be 

 combined about 250 of such elementary hair-fibres, if we do 

 not reckon the uniting cytoblastema, which, however, exists cer- 

 tainly, but in small quantity ; in its entire thickness, there- 

 fore, a human hair must contain a prodigious number of such 

 vessels. How this can be brought into agreement with the 

 number of the cells of the pulp is to me still inexplicable. The 

 breadth of the former is nearly ten times less than that of the 

 latter, and as the hair-fibres, are produced not by the splitting 

 but by the aggregation of the cells, the pulp must be ten times 

 greater than the developed hair, Vv^hereas, in fact, it only ex- 

 ceeds the hair-cylinder at most three times in thickness. I 

 was myself doubtful of the accuracy of my observations, and 

 was therefore induced to repeat them frequently ; but I have 

 always arrived at the same puzzling result, the explanation of 

 which I must leave to others. The artificial decomposition of 

 the perfectly developed hair afforded, besides the confirmation 

 of the view to which the history of the development in rela- 

 tion to the texture of the hair necessarily led, also some further 

 indications as to the seat of the colouring matter in the hair. 

 The dark colour of the lowest part of the pulp is plainly pro- 

 duced by the dark contents of its cells, while the cellular pulpy 

 matter which unites them is light coloured and transparent ; 

 and we can often merely conclude as to its presence without 

 being able to demonstrate it. The middle portion of the pulp 

 exhibits neither the intense coloration of the lowest part of 



