CUTAITEOrS NEBVE-TEEMESTATIONS IN MAMMALS. 557 



Nerves terminating in Branched Gells on Hairs. 

 This, tlie lowest in level upon the hair, and the first in order 

 which we tabulated, is an ending which bears very different re- 

 lations to the meduUated nerves according to the character of 

 the hair upon whose follicle they lie. In the first place, we may 

 remark that, as far as we can learn, no observer excejDt ourselves 

 seems to have noticed that such branched cells may be seen on 

 all the ordinary hairs, and that the latest, and, indeed, the only 

 investigators of this question, namely Arnstein and Bonnet, in 

 1878, and Merkel, in 1880, not only make no allusion to them, 

 but do not even show them in the drawings they give of nerve- 

 terminations on ordinary hairs. It is true that there such nerve-- 

 cells have neither the number nor regularity which make them so 

 prominent upon the feelers ; but their existence can none the 

 less be easily verified (c, figs. 6, 7, and 14). Indeed, when we 

 thought we were discovering nerve-endings upon the ordinary 

 hairs, these cells were the first objects to meet our eye. 



The oversight already referred to may also be due to another 

 special feature found on ordinary hairs. In some hundreds of 

 specimens of such terminations on ordinary hairs which we possess, 

 we have never yet come across an example where a medullated 

 nerve passes directly to one of these cells, as seems to be the inva- 

 riable rule in the case of the feelers. This may have led to their 

 existence being unnoticed — an oversight otherwise inexplicable. 

 In the feelers the connexion of the medullated nerves with these 

 cells is very apparent ; and it has been known under one de- 

 scription or another for the last ten years, although at the pre- 

 sent day the most diverse opinions as to their true nature are 

 held by all the observers who have specially investigated the 

 subject. As far back as 1866 Odenius thought that the nerves 

 terminated in an oval swelling ; but his opinion is given with a 

 certain amount of hesitation. Again, in 1872 Sertoli described the 

 nerves as terminating, after piercing the basement-membrane, in 

 stellate cells lying among the lower layers of epidermic cells 

 lining the hair-follicles. The observations thus made by this 

 author, although perhaps nearer the truth than any that liave 

 subsequently been made, have nevertheless been rejected by suc- 

 ceeding observers, none of whom apparently can agree in their 

 conception of these endings. 



Thus it is that we find Dietl, in 1873, describing the nerves as 



