THE SCIENTIFIC PAPERS OF 

 THOMAS HENRY HUXLEY 



I 



ON A HITHERTO UNDESCRIBED STRUCTURE IN 

 THE HUMAN HAIR SHEATH 



London Medical Gazette, vol. i. p. 1340, July, 1845 



In Professor Henle's " Bericht ueber die Leistungen in der His- 

 tologie," for 1846, the following passage is contained : — 



" Kohlrausch and Krause describe the inner layer of the sheath 

 of the root (of the hair) which I depicted as a glossy soft fenestrated 

 membrane, to be a layer of pale longish and flat cells, which firmly 

 adhere in the longitudinal direction, whilst transversely they may be 

 separated by manipulation, and then present the appearance of a 

 membrane with irregular gaps. This same membrane separated and 

 folded they considered to form the transverse strise on the root of the 

 hair. I venture to affirm that these observers have not even seen any 

 inner layer of the sheath of the root. I beg of them to treat a hair 

 torn out with both layers of the sheath adhering, with acetic acid ; 

 carefully to strip off the granular outer layer, which by this means is 

 rendered brittle, and then to adjust the focus of the microscope to the 

 most superficial part of the hair. They will then see, not only the 

 round holes with very even sharp borders described by me, but also, 

 by altering the focus, they will see beneath this the transverse strips, 

 which, as Meyer justly stated, are formed by the borders of imbricated 

 scales. I have also at times seen a layer consisting of anastomosing 

 longitudinal fibres, which perhaps is composed of elongated scales 

 but I cannot say whether this was in the place of my fenestrated 

 membrane. Certainly it is not ordinarily present." 



VOL. I B 



