558 BALDWIN SPENOER AND GEORGINA SWEET. 



the bulb becomes moulded, though there is still an indication 

 of the rim on the upper side not having grown down to quite 

 the level of the lower side. The nuclei are beginning to have 

 a definite arrangement ; those continuous with the stratum 

 Malpighii are set with their axes at right angles to the wall of 

 the follicle^ except on the outer surface of the latter, where, as 

 in all later stages, they have become apparently subject to stress, 

 resulting in their lying with their long axes parallel to the 

 length of the bulb ; on the inner surface of the latter, where 

 they lie upon the papilla, they are placed with their long axes 

 at right angles to the length of the latter. The central layer 

 of nuclei in the follicle are distinctly arranged with their long 

 axes parallel to the length of the follicle, while the outer 

 layers, on the contrary (as can be seen in transverse section), 

 show a tendency to elongation in the opposite direction. In 

 the bulb there is the earliest indication of the formation of 

 the hair itself. The nuclei of the outermost layer, that is those 

 lying on the dermic papilla, are continuous with a series which 

 lies in the central line of the hair rudiment, and around this 

 central series others are beginning to be arranged in somewhat 

 definite lines, giving the appearance of the hair rudiment just 

 beginning to grow up through the solid follicle. As in the one 

 which is figured, the follicle is often bent at a distinct angle to 

 the surface at the part where the swelling occurs, to which 

 reference has been made. It will be seen that this swelling 

 is particularly prominent in this follicle, and that considerable 

 growth relative to the other parts has taken place in the section 

 of the follicle above the bulb. 



Stage 5 (fig. 14). — This is an important stage, as in it 

 the hair rudiment, though unmistakably discernible in the 

 fourth stage, is now clearly marked out. Perhaps the most 

 striking point at the first glance is the development of pig- 

 ment in the layer next to the papilla, which has still more 

 clearly begun, as it were, to grow upwards in the centre of the 

 follicle, the nuclei becoming elongate and also taking the stain 

 more deeply than those surrounding them in the follicle. 

 Running up within the bulb, more or less definite lines can be 



