20 



PHYSIOLOGY 



CHAP. 



Meissner's corpuscles, which lie in the papillae and sub- 

 papillary layer of the corium, were discovered in 1852 by Meissner 

 and E. Wagner in the cutaneous papillae of the hands and feet. 

 Their structure is complex and very variable, so that, according 

 to Euffini, each corpuscle requires special description. They are 

 found in man and the ape, but have not been recorded in other 

 mammals. Usually they are oval or rather elongated. One, 

 two, or more medullated fibres run to the corpuscle and penetrate 

 its interior after winding round it once or twice, lose the myelin 

 sheath and the sheath of Schwann, and then form a spiral coil with 



a number of more or less irregular con- 

 volutions. The branches of the axis- 

 cylinder which make the spiral are often 

 very varicose, and have one or two ter- 

 minal enlargements (Fig. 8). The non- 

 nervous tissues of the corpuscle consist 

 in an external capsule of lamellated 

 connective tissue, and a homogeneous, 

 finely granulated interior, which is prob- 

 ably formed of fibrillary connective 

 tissue, with a number of nuclei. 



Many varieties of Meissner's cor- 

 puscles are known. Those last de- 

 scribed by Dogiel represent a transitional 

 form between the typical nerve -endings 

 of Meissner, which are collected in a 

 corpuscle enclosed in a capsule, and the 

 non - typical nerve - endings, which do 

 not form real corpuscles, but remain 

 mag : nTfie(T"(Ra"nvier.r~7i' ) w7two free within the papilla, without a sur- 



nerve- fibres, passing to the cor- -i i Ti r- i 



puscle; a, oj terminal varicose rOUlldmg Capsule ; these Wei'6 first de- 



"vTh?ntt;eTor P ufcie. axis " cylinder scribed by Euffini (1892) in the 

 papillae that contain no Meissner's cor- 

 puscles, under the name of papillary bulbs. Dogiel's corpuscles 

 consist of two parts : one closed, lying at the base of the papilla, 

 the other open towards its apex. The former differs in no respect 

 from the typical Meissner's corpuscle, the latter resembles one 

 of the many forms of free nerve - endings described by Euffini, 

 Sfameni, and others (Fig. 9). 



Special corpuscles were described by Golgi (1880) in peri- 

 tendinous connective tissue and the external perimysium of human 

 muscle. These were thoroughly investigated by Mazzoni (1891), 

 and are therefore known as the Golgi-Mazzoni corpuscles. Euffini 

 (1894) discovered that they are also present in subcutaneous con- 

 nective tissue, as well as in the subpapillary and papillary layers. 

 Their external form and dimensions vary ; they consist of a lamel- 

 lated capsule and an internal core of fibrillary connective tissue 



FI, x.-Meissners corpuscle in a 



