234 SKIN, HAIR, AND NAILS, BY ALFRED BIESIADECKI. 



pany with the bloodvessels, here and there penetrate particular 

 papillae that, as a rule, ar,e destitute of vessels, and terminate 

 in the so-called tactile corpuscles (Corpuscula tactus) of 

 Meissner and Wagner. 



If the skin covering the last phalanges be subjected to ex- 

 amination after being hardened in chromic acid, scattered 

 broad and but slightly elevated papillae will be met with, con- 

 taining oval corpuscles that equal the papillae in length, and 

 have a diameter of 0*02 to 0'045 of a millimeter. These (fig. 

 190) are conspicuous for their rigid aspect and their transverse 

 striation, which is partly owing to the presence of fine lines, 

 and partly to fusiform transversely placed and highly refractile 

 nuclei. A medullated nerve fibre enclosed in a sheath, con- 

 taining many nuclei, runs sometimes to the lower pole, some- 

 times as far as the middle, and sometimes even to the extremity 

 of the corpuscle, frequently winding once or more times round 

 the corpuscle which is constricted at these points. The nerve 

 at length suddenly loses its medulla, and is no longer capable 

 of being traced. 



Similar appearances are presented by fresh sections of skin 

 treated with potash, soda, or concentrated acetic acid. Many 

 points, however, yet remain undecided in regard to them, 

 and receive different explanations at the hands of different 

 observers. Thus the transverse lines are considered by some 

 to be caused by connective-tissue fibres; others regard them 

 as elastic fibres, and others as nerves ; whilst the transverse 

 nuclei are sometimes held to be connective-tissue corpuscles, 

 and sometimes the nuclei of nerve sheaths. The nerve sheaths 

 now become destitute of medullary substance, are again by 

 a few observers considered to enter a cavity within the tac- 

 tile corpuscle, and to end by free extremities after the fashion 

 of the corpuscles of Krause, that are elsewhere found. 



Specimens that have been prepared with chloride of gold, 

 enable us to give an explanation of some of the appearances 

 in question, since in these the nerve fibres assume a dark 

 violet colour, whilst the rest of the tissue becomes of a pale 

 red. The contours of the corpuscles are marked out by faint 

 outlines into areas within which are oblong nuclei. In fine 

 sections of the corpuscles, from four to six violet-coloured 



