EXPLANATION OF THE PLATES. 



PLATE XXIX. 



STRUCTURE OF HAIR. 



Fig. 1. A portion of the stem of a grey hair of the scalp, 

 magnified 350 diameters, showing the medullary 

 canal, the fibres of the stem, and the outer imbri- 

 cated scales. 



Figs. 2, 3. Transverse sections of hairs of the beard : mag- 

 nified 130 diameters. 



Fig. 4. The fibres of the stem of a hair : magnified 670 dia- 

 meters. It is most probable that these fibres 

 originate in the same way as those of the inner 

 sheath, viz. in nucleated cells. 



Figs. 5, 6, 7. Apices of hairs : figs. 6. and 7. represent, the 

 points of two hairs of the scalp, magnified 350 dia- 

 meters ; and fig. 5. that of one of the perineum. 

 All hairs taken from this region, as well as those 

 of the axilla, present similar obtuse extremities, 

 which probably result from the constant friction 

 to which they are subject in those situations. 



Figs. 8, 9. represent the roots of two hairs of the scalp 

 removed with the comb ; the sheaths, vesicle, and 

 lower portion of the bulb having remained behind. 

 All hairs removed with the comb and brush pre- 

 sent the same appearances, that of fig. 8. being by 

 far the most common form: magnified 130 dia^ 

 meters. 



Fig. 10. A hair from the whisker, magnified 130 diameters, 

 and containing two medullary canals. 



