NERVE FIBERS 



229 



enters the bulb. The end bulb of Krause measures from 

 Hooo to ^so 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 situa- 

 tions, corresponding 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 



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.) 



plantar surfaces ; they diminish in number proximally from 

 these points. They may be simple or compound according 

 as the enclosing capsule contains one or more collections of 

 nucleated cells. Their form is oblong with the long axis 

 in the direction of the papillae. They vary in thickness with 

 the papillae of the region in which they are located. They 

 may have a transverse diameter of from %oo to M.50 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 



