tain a nucleus. These scales render the hah* rough and coai'se, and so 

 break up the raj^s of light falling upon or passing through tt, that it 

 seems under ordinary circumstance to be quite opaque ; when, however, 

 these small crevices or roughness are filled up with water, or with grease 

 and the like, we have a smooth and glossy appearance, each hair reflect- 

 ing tlie light, and permitting it to pass through almost unbroken. This 

 explains why it is that the hair on some parts and some persons is more 

 glossy than on others, in consequence of the small size of the scales, and 

 the amount of oily matter filling up their angles. The structure of the 

 fibrous portion of the hair is not readily detected without manipulation. 

 At first sight it appears homogeneous, or at most to be marked by colour 

 cells. After maceration, however, in sulphuric acid, it may be readily 

 torn, and is then proved to consist of a number of fibres, of small 

 size and gi'eat tenacity, that pass from the root to the apex. The fibres 

 are united by cement and by the scaly coating. When either the one 

 or the other is destroyed by friction or age, the hair splits readily, as 

 may be seen in the long hairs of women or the perineal and axillar hairs 

 of man. 



I may mention, cursorily, that the fibrous appearance is very much 

 damaged by the specimen being placed in Canada balsam, and that it 

 must be examined freshly, or else kept in a liquid cell. 



In grey hair, a number of interstices exist between the fibres, which 

 contain air in some form or other. These are to be found sparingly in 

 the bulbs, but are not numerous enough there to account for their con- 

 stant presence in the shaft. I believe they are produced mainly by the 

 shrinking of the cement binding the fibres together. 



Kolliker has, I see, by a recent review, endeavoured to show that 

 these fibres are elongated nucleated cells. I am quite unable to confirm 

 his observations, the whole weight of evidence appearing to me to mili- 

 tate against this view. 



A great peculiarity exists in the hairs of the axilla and the perineum. 

 They ai'e there exposed to a great amount of friction, and are constantly 

 bathed with perspiration. The result of the former is, that the majority 

 are resolved into their fibrous elements, and many of them have large 

 holes torn in them from the separation of the fibres. The summits in 

 like manner are usually broken up into fibres, and more or less rounded 

 off. Some may be seen with these fibres perfectly loose, like a brush; 

 others have been united together by some exudation, and appearing not 

 unlike a knobbed stick. 



The result of the splitting of the hair itself is the accumulation of 

 matter on their exterior surface in an extremely irregular manner. The 



