ITS CHEMICAL RELATIONS. 61 



more rarely, round cells, which, after the above-mentioned treat- 

 ment with potash, are seen to contain dark fat-like granules, in 

 addition to a clear roundish or oval speck (the rudiment of a 

 nucleus). Many of these roundish grey granules are observed 

 between these cells in fresh hair that has not been treated with 

 potash. Kolliker* has shown by several admirable experiments, 

 that the dark granules which occur in coloured as well as in white 

 hair, are for the most part mere cavities filled with air occurring 

 between and in the dried medullary cells. 



Such are the most important histological grounds on which 

 a rational chemical examination of the tissue of the hair must be 

 based. Unfortunately, however, chemists have hitherto been 

 unable to analyse the hair when considered from this point of 

 view. We have some admirable observations on this subject by 

 Schererf and van Laer,{ who, although they have not investigated 

 the chemical constitution of these parts in accordance with histo- 

 logical requirements, have yet exhibited the great analogy subsist- 

 ing between the substance of the hair and other horny tissues, and 

 have, moreover, successfully elucidated several important points 

 involved in the inquiry. 



Scherer's elementary analyses of the hair correspond with 

 those of Lae'r, excepting that there is a slight difference in the 

 amount of hydrogen : 



Carbon 50'65 



Hydrogen 6'36 



Nitrogen 17'14 



Oxygen 20'85 



Sulphur 5"00 



Like most other horny tissues, the hair dissolves, with the 

 exception of a few fine molecules, on prolonged digestion in a 

 solution of potash, there being at the same time a development of 

 ammonia. The solution yields on the addition of acetic acid a 

 slight deposit, which is a less oxidised protein-compound than the 

 far more considerable precipitate produced by the addition of a 

 larger quantity of acetic acid ; the latter, which is Mulder's 

 deutoxide of protein, contains sulphur, and entirely agrees in its 

 reactions with the substance which is obtained by the precipitation 

 of the alkaline solution of other horny tissues on the action of 



* Op. cit. p. 115. 



t Ann. d. Ch. u. Pharm. Bd. 40, S. 58-03. 



Ibid. Vol. 45, pp. 147-183. 



