THE SKIN. 



281 



be two or more corpuscles within a single papilla (Thin), but 

 each corpuscle invariably has a special nerve passing into it. 

 Frequently, however, an appearance as if two corpuscles were 

 present is produced by a single corpuscle having the shape 

 of a figure 8. The medullated nerve-fibre, in passing to the 

 corpuscle, pursues a more or less curved course, and usually 

 enters it at or near its lower extremity. It may, however, en- 

 ter at any part of the corpuscle, and sometimes winds around 

 it for a considerable distance before entering. After entering 

 the corpuscle the medullary sheath is lost, and its course now 

 becomes difficult to pursue, except in the case of very small 

 or young corpuscles. The intimate structure of these bodies 

 and the arrangement of their formative elements are still mat- 

 ters of discussion and uncertainty. The external portion of a 

 corpuscle appears to be composed, in great part, of larger or 

 smaller bundles of white, fibrous connective tissue anastomos- 

 ing with each other and running transversely, or in a spiral 

 direction, to the long diameter of the corpuscle. This part 

 of the corpuscle differs, as regards 

 irregularity of surface, with the size 

 and the manner in which the fibrous 

 fascicles divide and anastomose. The 

 coarser the bundles and the anastomo- 

 ses the more irregular will be its sur- 

 face. Between the fibres are found 

 oval or round bodies which color deep- 

 ly in gold, and have been regarded as 

 elastic elements (Thin). Other obser- 

 vers consider them as connective tis- 

 sue, or nerve-fibres. Some of these 

 bodies undoubtedly represent the 

 nerve-fibre in transverse or oblique 

 section ; for the nerve pursues a more 

 or less zigzag course within the corpuscle, and, consequently, 

 a section of the body will probably show the nerve cut across 

 in one or more places (Fig. 120, Z>). The arrangement of the 

 elements forming the central part of the corpuscle is not yet 

 thoroughly understood. These bodies have hitherto been 

 usually regarded as end-organs that is, it has been believed 

 that the medullated nerve-fibre terminates within the corpuscle, 

 hence the name, tactile corpuscle. Observers, however, have 



f... 



FIG. 120. Tactile corpuscle, show- 

 ing termination of nerve : a, corpuscle; 

 6, nerve, cut obliquely; c, apparent 

 division of nerve-fibre ; e, similar ap- 

 pearance as at c ; /, blood-vessel ; g, 

 rete cells; h, nerve-fibre cut trans- 

 versely. 



