26 PHYSIOLOGY CHAP. 



like enlargements (Fig. 18). The nerves of human hair have not 



Fi. 17. Ruffini's corpuscle, in which the fibres penetrate into one end of the spindle. (Ruffini. 

 C., Capsule ; H., sheath of Henle ; s.t., sustentacular tissue ; n.e., nerve-ending. 



yet been described and studied ; but everything leads us to con- 

 clude that they are similar to those of the hairs of other mammals. 



As regards the specific sensory 

 function of the several forms of 

 cutaneous nerve-endings, it must be 

 confessed that our knowledge has 

 made little progress. The peripheral 

 organs for appreciation of pressure 

 are undoubtedly represented in all 

 parts of the skin provided with hairs 

 by the above-described nerve-plexus 

 in the outer sheath of the hair-root. 

 Blix, and more recently v. Frey, 

 have demonstrated that a pressure 

 point corresponding with each hair 

 lies near the point at which it 

 emerges, on that side from which 

 the hair follicle slopes. 



In regions that have no hairs 

 it can be affirmed with great prob- 

 ability that Meissner's corpuscles 

 correspond to the pressure points. 

 The results of Blix and v. Frey in 



FIG. 18. Section through a hair and hair 

 sheath of cat magnified 160 times. 



(Bolim.) pi., Nerve plexus; AT., nerve; f ar> 4- ormoa witli fho nlrl IH'PW rm 

 7/., hair; t.i., tunica interna of root of I a _ ct agree Wit ll tne OKI V16W On 

 hair; i.e., tunica externa ; h.L, hyaline 

 layer. 



always 



Meissner's corpuscles were 

 held to be tactile. 

 Their superficial position in the skin corresponds to the 

 sharp demarcation of tactile points, to their accessibility, un- 

 like the nerve-plexus of the hairs, to electrical stimuli, and 



