326 MANUAL OF HISTOLOGY. 



Arnold believes, however, that in very many cases these fibrill?e leave 

 the nucleoli again in an opposite direction, and after having traversed 

 the nucleus and body of the cell, unite once more with the intramuscular 

 network. According to this, the nucleolus would appear to be not the 

 terminal point, but only a knot on the ultimate filament. 



Later on we shall have to discuss the reticulum of the corneal nerves. 



We must now turn to the consideration of the nerves supplying glands, 

 which were discovered by Krause. Here, besides dark-edged fibres which 

 occur in the salivary and lachrymal glands of mammals, and come to an 

 end in peculiar terminal structures, to be referred to again ; besides these, 

 pale nucleated nerve fibres, only about O0020 mm. in diameter, may be 

 remarked between the glandular follicles, and applied, with dual division, 

 to the so-called membrana propria of the gland element. These fibres just 

 described take their origin from dense networks of medullated tubes 

 situated around the excretory ducts of the lobules. 



Finally, it is stated by Pfliiger that in the salivary glands the delicate 

 end filaments of the nerve fibres terminate in the gland-cells after piercing 

 the membrana propria. He has also seen the processes of multipolar 

 structures, lying external to the follicles, coming to an end in the same. 

 These he supposes to be ganglion cells. The same observer states that 

 a similar arrangement of parts is to be seen in the pancreas. In the liver 

 also he has found a connection between the nerve fibres and gland cells. 

 Between the cells likewise of the lacrymal gland, a radiation of fine 

 terminal fibres has been described by Boll. We regret being obliged to 

 express our incredulity as regards the correctness of all these statements ; 

 in our opinion, the termination of the nerve filaments in glands is still 

 unknown. 



REMARKS. Philos. Trans, far the year 1863, part ii. p. 562. 



184. 



The final destination of the sensory nerve fibre, to which we now turn, 

 is found to be in the first place a special terminal structure the 

 extremely abstruse and much-disputed question of their bearing in most 

 of the organs of special sense we leave out of the question in the next 

 place, it seems probable that the fibre may end with free ramifica- 

 tions. . 



The best known anatomical recipients of the sensitive nerves are (1) 

 the Pacinian bodies ; (2) the tactile corpuscles of Wagner and Meissner ; 

 and (3) the terminal bulbs of Krause. The first of these, the oldest 

 discovery, present the greatest complexity of structure; the last or 

 newest, the least. 



The terminal bulbs of Krause (fig. 314) are found in the human being 

 on the sensitive nerves of the mucous membrane and in the skin. They 

 are met with again in the conjunctiva bulbi, in the mucous membrane at 

 the base of the tongue, in the fusiform and circumvallate papillae of the 

 latter, and in the soft palate, glans penis and clitoris. In the mam- 

 malian body they are also widely distributed. They have been also 

 met with in the external skin, as, for instance, in that of the mouse, and 

 they occur on the volar aspect of the Guinea-pig's toes. Their nature, 

 moreover, is the same in the mammalia as in our own frame. 



The form of these structures in the mammal is egg-shaped (1, a), 

 0-0751-0-1409 mm. in length, and (2 a) about one-fourth as broad. In 

 man and the monkey they are more rounded, their diameter being from 



