564 DBS. GEOEGE A1S"D EEAJiTCES E. HOGGAN OK 



appeared to have length without breadth ; aud to make them evi- 

 dent we have given them more body and distinctness than they 

 appeared to possess in the original. They form fit objects for 

 comparison with fig. 7, an ordinary hair nerv^e-apparatus from 

 the nose of an adult Horse, all of them having been drawn under 

 the same magnifying-power. In connexion also with the identity 

 which we shall draw between the forked terminations on hairs and 

 the inner circle of fibrils in the organ of Eimer (fig. 1, if), this 

 developing nerve-ajjparatus of the hair is most instructive. 



In the feeler-hairs the ganglion-cells (figs. 11 and 12) appear 

 to have reached their permanent position at birth ; but in one 

 case, in the Rabbit, we were able to see them in a half -grown foetus 

 lying at the bottom of the hair-follicle in masses. The course of 

 development of both kinds of end organs may also be considered 

 well illustrated in our fig. 9, from the lower lip of the Water-Shrew. 

 The nerve-apparatus shown there belongs to what may be called 

 an aborted feeler-hair, or feeler in course of development, being 

 in a condition midway between feelers and ordinary hairs, and 

 showing the two kinds of nerve-terminal organs in their simplest 

 form. 



In that feeler the forked terminations / are as yet stunted and 

 lying in the same zone as, or even upon a lower level than, that 

 of the ganglion-cells. These cells amount as yet only to one cell, 

 c, upon each of the two bifurcations on each nerve. 



If development had proceeded further, as it was likely to do, 

 other cells would probably have become developed on each nerve- 

 bifurcation, until a number similar to that seen in fig. 11 were 

 seen there. The forked terminations would also probably have 

 passed further on, so as to occupy the upper instead of the lower 

 border of the swelling on the hair-follicle. This growth would 

 probably take place by direct growth of the axis-cylinder peri- 

 pherally, and the interposition of an additional myeline-segment 

 between two of the existing segments*. 



Joberfs Coil of Nerve-fibrils surroimding Follicle. 

 This arrangement of nerve-fibrils (seen at j, figs. 4, 5, and 7, 

 Plate XIII.) appears to have been the form in which nerves were 

 first perceived upon hairs, aud was first described by Jobert, who 

 observed it on the fine hairs, almost microscopic in size, that are 

 found on the tails of albino Eats. He imagined that that was the 

 only part of the body in which such terminations were found, as 

 * See our two articles referred to on p. 536. 



