36 NERVOUS SYSTEM. 



with a certain amount of caution, until they shall have been 

 amply confirmed. 



The researches of Pfliiger upon the salivary glands leave 

 no doubt as to the fact that medullated nerve-fibres pass to 

 the cells of these organs and there abruptly terminate, at 

 least as dark-bordered fibres. This author believes, how- 

 ever, that, having formed a more or less branching plexus, 

 non-medullated fibres pass directly into the glandular cells, 

 and he gives figures which seem to illustrate this arrange- 

 ment pretty clearly. The same observer describes and fig- 

 ures multipolar cells, mixed with the glandular cells, in 

 which some of the nerve-fibres terminate. 1 



Modes of Termination of the Sensory Nerves. There 

 are undoubtedly several modes of termination of the sensi- 

 tive nerves in integument and mucous membranes, some of 

 which have been accurately enough described, while others 

 are still somewhat uncertain. In the first place, anatomists 

 now recognize three varieties of corpuscular terminations, 

 differing in their structure, probably, according to the differ- 

 ent functions connected with sensation, with which the parts 

 are endowed. In addition, it is probable that many sensi- 

 tive nerves are connected with the hair-follicles, which are 

 BO largely distributed throughout the cutaneous surface. 

 There are, also, terminal filaments not connected with any 

 special organs, some of them, perhaps, ending simply in free 

 extremities, and some connected with epithelium. There is 

 still considerable difference of opinion among anatomists 



1 PFLUGER, in STRICKER, Manual of Human and Comparative Histology, Lon- 

 don, 1870, vol. i., p. 433, et seq. The views here advanced by Pfliiger have been 

 confirmed by him in more recent observations and extended to the pancreas 

 (Journal of Anatomy and Physiology, Cambridge and London, 1870, vol. iv., p. 

 156). Pfliiger states, also, his belief that the same connection exists between the 

 nerves and the liver-cells (ibid., p. 188). The question, however, is still some- 

 what uncertain, and Mayer, in examinations of the salivary glands, found fila- 

 ments in connection with the nuclei, but failed to satisfy himself that they were 

 nervous (Quarterly Journal of Microscopical Science, London, April, 1870, p. 199) 



