212 PRACTICAL HISTOLOGY [XXVII 



(Lesson xvi. 5). Harden in alcohol, imbed, cut sections. Note 

 the nerve plexus in the sub-cutaneous tissue and the bundles 

 of nerve fibres which proceed from it to the large hairs (sinm or 

 tactile hairs}. 



Note further the superficial nerve plexus in the upper part of 

 the dermis, and the small bundle of nerve fibres sent downwards 

 to the smaller hairs ; the nerve fibres form a ring around the hair 

 just below the duct of the sebaceous gland. 



In successful preparations (and better in successful methylene 

 blue preparations) the non-medullated branches of the deep nerve 

 fibres may be followed forming spatula-like endings, partly outside 

 the hyaline membrane, partly amongst the cells of the outer layer of 

 the root sheath ; and in the region of the ' ring ' a close plexus of fine 

 varicose fibrils may be seen. 



7. Section of the beak of a young duckling (Flemming's 

 fluid, picrocarmine). Note 



The simple form of touch corpuscles (Grandry's corpuscles) 

 just below the epidermis, consisting of two or three disc-shaped 

 cells to which a medullated fibre runs, ending in a non-medullated 

 expansion between each two cells. 



The simple forms of Pacinian corpuscles (Herbst corpuscles) ; 

 they are smaller than Pacinian bodies and have fewer capsules ; 

 a row of nuclei is seen in the core on either side of the axis 

 cylinder. 



8. Special nerve endings in the epidermis. Cut out the 

 hairless skin of the snout of a freshly killed mole, and treat 

 it with gold chloride (25 p.c. formic acid 10 minutes, gold 

 chloride to f hour, wash in water, 25 p.c. formic acid in the 

 dark for a day, wash, pass through alcohols). Cut sections of 

 one piece at right angles to the surface and another parallel to 

 the surface. 



(a) Note in the vertical section (h.p.) 



The downward projections of the epithelium. The medullated 

 nerves running to each projection, there losing medulla, and 

 continuing on, in the middle of the projection between the 

 epithelial cells, as a bundle of varicose fibres ; in the outer part 



