586 DES. GEORGE AND FRANCES E. HOGGAN ON 



among wHcli tKey lie, tlieir appearance becomes greatly altered. 

 Moreover, on being broken off from tlieir centres, tbese nerve- 

 cells probably die and degenerate, tbus accounting for tbe intense 

 pigmentation they acquire from tbe action of the gold solution. 



Save the Intraepidermic Nerve-jibres any Function ? 

 Just as we look upon the cells of Langerhans as dead elements, 

 so, in opposition to the whole histological world, are we inclined 

 to look upon the intraepidermic nerve-fibrils as practically use- 

 less ; for it is rather unusual to look upon broken nerve-fibres as 

 capable of performing their normal functions. From what we 

 have said, it must be clear to every one that the free ends of these 

 nerves, in the epidermis, are due to unnatural causes, which ought 

 to have put an end to functional activity, and that after they reach 

 the stratum granulosum structural death has also overtaken them. 

 That they retain vitality and a capacity for growth up to that 

 layer we quite believe ; and the proof of it lies in the fact that, 

 short of it they endeavour to push out lateral offshoots, which, 

 like themselves, are carried into the stratum granidosum to be 

 destroyed. This fact brings us back to Professor Ranvier's hypo- 

 thesis as to direction of growth in the intraepidermic nerve-fibrils, 

 and the continuous or uninterrupted character of that growth 

 (p. 576), to which we promised to return. 



Professor Sanvier^s Hypothesis of Growth of Intraepidermic 

 Nerve-fihrils negatived. 



We have already shown that these nerves, instead of having the 

 power to grow through the epidermis and carry on continuous 

 evolution, as stated by Eanvier, are really passive agents, and are 

 dragged into and through the epidermis to their destruction, in 

 opposition to their own natural tendency to lateral growth, as 

 shown in the position of the whole subepidermic plexus of nerves 

 and nerve-cells (see fig. 24, Plate XV.). 



Apart, however, from any argument to be derived from the 

 position of that plexus, we have this further proof, shown while 

 the nerves are being dragged through the epidermis. If the 

 breakage occurs while the arch or nerve lies among the lower 

 layers of cells in the epidermis, the broken end at once begins to 

 push out lateral branches in every direction, as if anxious to 

 form a junction with any other nerves in the neighbourhood. A 

 striking example of this kind is seen in the nose of the kitten, of 

 which we give a drawing in fig. 24, Plate XV., which speaks for 



