572 



NERVOUS SYSTEM. 



system, which contains numerous fibres of Remak the terminations of which have not 

 been described, it is evident that our information concerning this part of the peripheral 

 nervous system must be incomplete. Perhaps the most remarkable of the late observa- 

 tions upon this point are those of Dr. Frankenhaeuser, upon the nerves of the uterus. 

 These researches were very elaborate ; but the point most interesting in this connection 

 is that the nerves, having formed a plexus in the connective tissue, send exceedingly 

 small fibres into the sheets or layers of muscular-fibre cells, which branch and finally go 

 into the nucleoli of these structures. Arnold has confirmed these observations and has 

 shown farther that, in many instances, the fine terminal nerve-fibres branch and go into 

 the nuclei of the muscular fibres and then pass out to join with other fibres and form 

 a plexus. 



Termination of the Nerves in Glands. The great influence which the nervous system 

 exerts upon secretion attaches considerable interest to recent researches into the ultimate 

 distribution of the nerves in the glands. It must be remembered, however, in these, as 

 in all observations upon the destination of the smallest nerve-fibres, that the problem is 

 one of the most difficult in the whole range of minute anatomy ; and the results arrived 

 at must be received with a certain amount of caution, until they shall have been amply 

 confirmed. 



FIG. 177 Termination of the nerves in the salivary glands. (Pfliiger.) 



I, II, branching of the nerves between the glandular cells ; III, terminations of the nerves in the nuclei of the cells ; 



IV, multipolar nerve-cell. 



The researches of Pfluger 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, however, 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 arrangement pretty clearly. The same 

 observer describes and figures multipolar cells, mixed with the glandular cells, in which 

 some of the nerve-fibres terminate. 



Modes of Termination of the Sensory Nerves. There are undoubtedly several modes 

 of termination of the sensitive nerves in integument and in 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 different functions connected with 

 sensation, with which the parts are endowed. In addition, it is probable that many 

 sensitive nerves are connected with the hair- follicles, which are so largely distributed 



