TACTILE CORPUSCLES. 41 



strise on the surface of the corpuscles are produced exclusively 

 by nerve-fibres. According to Kolliker, the tactile corpuscles 

 consist of a central bulb of homo- 



FIG. 5. 



geneous or slightly granular con- . ^ 



nective-tissue Substance, analo- 

 gous to the central bulb of the 

 Pacinian corpuscles, and a cov- 

 ering. Treated with acetic acid, 

 the covering presents numerous 

 elongated nuclei arranged in a 

 circular manner, which he be- 

 lieves to be nuclei of connective 

 tissue, and a few fine elastic fibres. 

 One, two, and sometimes three 

 or four dark-bordered nerve-fibres 



Cutaneous papilla. er, cortical layer with 



paSS from the SubcutaneOUS ner- plasmatic cells and fine elastic fibres ; 



&, tactile corpuscle, with transverse 



VOUS pleXUS tO the base Of each nuclei; c, afferent nervous branch, 



__.. with its nucleated neurilemma ; c?, 



COrpUSCle. liiese SUrrOUnd the nerve-fibres encircling the corpuscle: 



. e, the apparent termination of one of 



COrpUSCle With two Or three Spiral these fibres. (KOLLIKER, Hanflbnc.il 



der GewebeMire, Leipzig, 1S67, S. 106.) 



turns, and terminate by pale ex- 

 tremities at the surface of the central bulb. 1 This arrange- 

 ment is shown in Fip\ 5. 



O 



Rouget believes that the spiral lines on the surface of 

 the corpuscles are produced exclusively by gelatinous, nu- 

 cleated nerve-fibres which cover them completely, some- 

 times dividing and sometimes remaining single, and that 

 the fibres terminate in a nucleated central mass, entirely 

 analogous to the nucleated expansion of the motor nerves. 

 He claims to have demonstrated this in preparations 

 treated for two or three days in a liquid containing one drop 

 of acetic acid in about three and a third fluidounces of water, 

 and afterward washed in pure water, which denudes the 

 papillae of their epithelium. 2 In his endeavor to establish a 



1 KOLLIKER, op. cit., p. 138. 



2 ROUGET, Memoire sur les corpuscles nerveux qui se rencontrent d Vorigine des 

 nerfs sensitifs, dans les papilles de la peau et des muqueuses, Archives de physi- 

 ologie, Paris, 1868, tome i., p. 599. 



