THE TISSUES. 



branches lose their medullary sheaths and undergo further di- 

 vision, often dividing repeatedly. The nonmedullated nerves re- 

 sulting from these divisions, the majority of which are varicose, 

 form a most complicated network, the whole nerve network pre- 

 senting a structure which resembles a tangle of fine threads. 

 In the meshes of this network is found the semifluid substance 

 of the core. Now and then some of the larger fibers of the 

 network leave the corpuscle and terminate in neighboring cor- 

 puscles, or pass to the epithelium, where they end between the 

 cells. 



These three sensory nerve-endings end-bulbs of Krause, 

 Meissner's tactile corpuscles, genital corpuscles are, as Dogiel has 

 stated, very similar in structure. Each has a thin connective -tissue 

 capsule, surrounding a core, consisting of a semifluid substance, 

 concerning which our knowledge is as yet imperfect. One or sev- 

 eral medullated nerves go to each corpuscle, which, after losing 

 their medullary sheaths, divide and subdivide into numerous fine 

 varicose branches, which are variously interwoven, forming a more 

 or less dense plexus of interlacing and, according to Dogiel, anas- 

 tomosing fibers. The chief differences are those of form and size, 

 and of position with reference to the epithelium. Of the three forms 

 of endings, the genital corpuscle is the largest, and occupies the deep- 

 est position in the subepithelial connective tissue ; Meissner's cor- 

 puscle is intermediate in size, and is found immediately under the 

 epithelium ; while the end-bulbs of Krause are the smallest of these 



Fig. 139. Cylindric end-bulb of Krause from intermascular fibrous tissue septum of cat; 



methylene-blue stain. 



three forms of sensory endings and may be found in the papillae or 

 in the deeper connective tissue. 



A somewhat smaller nerve-ending of long, oval, or cylindric 

 form, known as the cylindric end-bulb of Krause, is found in various 

 parts of the skin and oral mucous membrane, in striated muscle 

 and in tendinous tissue. These corpuscles consist of a thin nucle- 

 ated capsule, investing a semifluid core. The nerve-fiber, after 

 losing its medullary sheath and fibrous sheath (the latter becomes 

 continuous with the capsule), passes through the core, generally 

 without branching, as a naked axis-cylinder, terminating at its end, 

 usually in a small bulb. (Fig. 139.) 



The majority of trre sensory nerve-endings with well-developed 



