82 PHYSIOLOGY CHAP. 



endless series of transitional forms which pass imperceptibly from 

 the typical Pacinian corpuscle to more elaborate and diffuse 

 nerve-endings. There is accordingly no fundamental difference 

 in their structure, and they can all be referred to the following 

 uniform type : " A nerve -organ, provided with, or destitute of, a 

 sheath of connective tissue, and consisting of one or more nerve- 

 fibres, which after losing their medullary sheath (if myelinated) 

 expand within and around a granular and nucleated substance." 



Three points here deserve consideration : 



(a) Sfameni neglects the nerve -fibres which are distributed 

 to the epithelium, because they are invisible by the gold chloride 

 method of staining, which he adopted. The intra- papillary 

 nerve-endings show certain small differences between one region 



FIG. 27. Fio. 28. 



FIGS. 27 and 28.- Papillae of clitoris of female. (Sfameni.) n.r., granular reticulum ; 

 p.t., papillary tuft, the branches of which are lost in the network. 



and another ; in the clitoris, e.g., there are more nerve elements, 

 and also more elaborate forms of nerve -endings, than in the labia 

 miriores. In all cases the papillae are supplied by a double system 

 of myelinated and non-myelinated fibres, which arise in the super- 

 ficial plexus. Both kinds of fibres expand in the papilla, some- 

 times in the irregular form of a granulated network (Fig. 27), often 

 in a perfectly regular form which simulates a true end-bulb. In 

 addition to these nerve -endings others may be found which 

 resemble very simple Meissner's corpuscles, as well as forms 

 analogous to the papillary nerve plexus which Kuffini described 

 in the finger-tips (Fig. 28). Within the network certain cellular 

 formations are to be seen, some of which stain with gold chloride 

 almost like the nerve-fibres (Fig. 29), and which can be seen in 

 direct continuity with the nerve network. According to Sfameni, 

 therefore, these must be true nerve -cells, and not connective 

 tissue-cells, as some have asserted. 



