SENSORY NERVE-ENDINGS. 



81 



and ridges of the connective tissue stratum of the skin and lie close beneath 

 the epidermis, with their long axises perpendicular. They are elongated 

 irregular ellipsoids, often somewhat sinuous in outline, and, in the larger 

 papillae, two may be joined at the deeper 

 ends to form a compound body. The 

 tactile corpuscles are relatively large, 

 being from 80150 ^ long and about one- 

 third as broad. Depending upon its size, 

 each corpuscle receives from one to four 

 nerve-fibres, which usually enter in the 

 neighborhood of the deeper pole and, on 

 piercing the capsule and losing the med- 

 ullary coat, divide into a number of naked 

 axis-cylinders. These pass in parallel or 

 spiral windings, beset with varicose thick- 

 enings, between the flattened tactile cells, 

 the entire interlacement being embedded 

 within a semifluid substance and enclosed 

 by a thin nucleated fibrous capsule. 



The End-Bulbs. These endings 

 include a variety of irregularly spherical 

 or ellipsoidal bodies found in the edge of 

 the eyelid, the conjunctiva and corneal 

 margin, the lips and oral mucous mem- 

 brane, the glans penis and clitoridis and 

 probably other parts of the integument 

 highly endowed with sensibility. In the 

 conjunctiva, they lie superficially placed 



FIG. 112. Corpuscle of Meissner lying with- 

 in papilla of conum of skin from finger ; only 

 deeper layers of overlying epidermis are 

 shown ; n, entering nerve-fibre. X 270. 



within the connective tissue near the summit of the papillae and folds, where 

 such elevations exist, but always close beneath the epithelium. They vary 

 considerably in size, often being small but sometimes measuring from 50 



loo fj. in diameter. Usually a single nerve- 

 fibre, exceptionally two or even more, enters 

 each bulb, losing its medullary coat as it 

 pierces the thin fibrous capsule. Within the 

 latter the nerve, now represented by the naked 

 axis-cylinder, divides into from two to four 

 branches, which, after describing several an- 

 nular or spiral turns, give off varicose fibrils 

 that divide into the terminal threads, forming 

 an intricate maze within the semifluid sub- 

 stance (granular in preparations) enclosed by 

 the fibrous capsule. 



The Genital Corpuscles. These end- 

 ings are most numerous (from one to four to 

 the square millimeter) in the deeper strata of 

 the corium covering the glans penis and clito- 

 ridis, but occur also in the skin of the neigh- 

 boring parts of the genitalia. They are of 

 irregular oval or lobulated outline and from 

 .02-. 35 mm. in diameter. They present the same general architecture 

 as the end-bulbs, but are larger and possess a somewhat thicker capsule 

 and contain a more intricate interlacement of the terminal nerve-fibrillae. 



FIG. 113. Two end-bulbs of Krause 

 from human conjunctiva. (Dogiel.) 



