229 



NERVE FIBERS 



the bulb. The end bulb of Krause measures from yoV(r to 

 of an inch in diameter. 



(c) The tactile corpuscles of Meissner have to do with the 

 sense of touch, and are situated largely in the papillae of the 

 skin covering the palmar surfaces of the hands and the plantar 

 surfaces of the feet ; they also exist in other situations, correspond- 

 ing in general to the distribution of the Pacinian corpuscles. 

 The largest number is found over the distal phalanges of the 

 fingers and toes on their palmar and plantar surfaces; they 



FIG. 72. Drawing from a section of injected skin. 



Showing three papillae, the central one containing a tactile corpuscle, a, which is 

 connected with a medullated nerve, and those at each side are occupied by vessels. 

 (From Yeo after Cadiat.) 



diminish in number proximally from these points. They may 

 be simple or compound according as the enclosing capsule con- 

 tains one or more collections of nucleated cells. Their form is 

 oblong with the long axis in the direction of the papilla. They 

 vary in thickness with the papillae of the region in which they 

 are located. They may have a transverse diameter of from 

 "50 o to T 4-^ of an inch, and probably in most instances occupy 

 the secondary eminences of the papillae in which they are found. 

 A simple papilla does not generally possess both vascular and 

 nervous loops. 



(d) The tactile menisques are found in certain cutaneous 

 regions. Nerves in the superficial layer of the skin lose their 



