894 



ORGANS OF THE SENSES. 



from these facts the tactile bodies, etc., would seem to be the 

 seat of sensibility. 



We also find larger corpuscles in the sub-cutaneous connec- 

 tive tissue and deep in the dermis, hanging from the nerve 

 tubes like fruit from the twigs of a tree, 

 and visible to the naked eye. These 

 are the corpuscles of Pacini: they 

 are surrounded by several fibrous 

 envelopes (Fig. 102), and have an 

 elongated cavity in which one or 

 several nerve filaments terminate in 

 a manner not yet perfectly under- 

 stood. They are found chiefly in the 

 palm of the hand, in the path of the 

 collateral nerves of the fingers; their 

 presence in various other organs, 

 however, especially in the mesentery 

 of the cat, leads us to doubt their 

 value as organs of tactile sensi- 

 bility. 



Kolliker has attempted to prove 

 that these various corpuscles all be- 

 long to the same type, being com- 

 posed of similar essential parts, 

 namely, 1, terminal nerve fibres (one 

 or several pale tubes), one end of 

 which is always free, and often en- 

 larged in the shape of a club ; 2, an 

 internal bulb or central mass, formed 

 of a kind of connective tissue, and 

 serving as a support or envelope of 

 the nerve fibre; 3, an enveloping 

 sheath of connective tissue. 



adipose tissue of the pulp of RoUQjet is Very justly opposed to 

 the lingers* ,. . _ , ' . X * f . 



this idea of the assimilation of the 



various corpuscles ; his histological researches have convinced 

 him, 1, that there is no real analogy between the structure 

 of the tactile corpuscles (and the corpuscles of J&ause), with 



* Primitive nerve fibre, containing medullary substance, rc, having a marked 

 outline, and a thick nerve sheath, p,p, which contains longitudinal nuclei, and 

 forms the tail of the corpuscle. C, The corpuscle proper, with its concentric 

 layers formed by the envelope of the nerve swollen into the shape of a club, and 

 having a central cavitv, into which the axis-cvlinder passes and is terminated. 

 150 diam. (Virchow.) 



