18 



PHYSIOLOGY 



CHAP. 



subpapillary and papillary layers. Some nerve-endings even reach 

 the rete mucosum of the epidermis, more exactly the stratum 

 germiuativum or layer of cylindrical, cells and the prickle or 

 polyhedral cells, where they end not in complex corpuscles but 

 in simple swellings or bull is. 



The following table from Ruffiui, adopted also by Crevatin and 

 Dogiel, indicates the topography of the different nerve-endings 

 present in the various layers of human skin : 



81 



Stratum corneum 

 Stratum lucidum 



Rete mucosum 



/Stratum granulosum 



I 



. f Layers without nerves. 



I Layer of prickle cells . 1 Layers of longer nerves. 

 (.Stratum germinativuin . J Hederiform expansions. 



t. - 



* i* 



B o 



_ -T 



o 8 



09 



/Basement or supporting membrane. 

 Papillary layer .... 



Subpapillary layer . 



Reticular layer . . . . 



Layer of panniculus adiposus . 



corpuscles. 

 Dogiel's corpuscles. 

 "j Euffini's papillary endings. 

 iQolgi-Mazzoni corpuscles. 



(" Meissner's corpuscles. 



! Dogiel's arboriform terminations. 



iGolgi-Maz/oni corpuscles. 



Dogiel's arboriform terminations. 

 rPacini's corpuscles. 



I Golgi-Max/.oni corpuscles. 

 Ruttini's organs. 

 ^Dogiel's arboriform terminations. 



As shown in this table, the most superficial nerve-endings of 

 the skin lie in the two deepest layers of the rete mucosum or 

 Malpighiau layer. Langerhans (1868) first saw that certain 

 nerve -fibres, after losing their myt-lin sheath, penetrate the 

 epidermis to form a network with loose meshes, and then spread 

 in independent and varicose branches through the epithelium, to 

 the outer limit of the layer of prickle cells, where they terminate 

 in bulbs (Fig. 6). Phylogene tie-ally, these represent the oldest 

 form of nerve-endings in the vertebrate epidermis. 



The so-called hederiform nerve-endings lie in the Malpighiau 

 layer close to the sweat-glands. The nerve-fibres of which they 

 are formed come from the superficial plexus of the skin. Near 

 the epithelium they lose the rnyelin sheath, and divide into 

 branches, which spread and twist between the prickle cells and 

 terminate according to the latest work of Dogiel in baskets or 

 nets (Fig. 7). Frequently, but not always, a cell of peculiar 

 appearance is found within the basket, which Eanvier and Dogiel 



