701 



THE \ /:/ 



bo, thoro is novor any fusion of the nervous runni. eules. but sin pic aj 

 tion of their fibres, \vliic-h always preserve their ind< pcndciicc, charact< rs, 

 and special properties. These anastomoses, tlicn, dilVer essentially from 

 thoso of arteries, and never permit two trunks to mutually supplement each 

 other when the course of one is interrupted. 



The nerves destined to the organs of vegetative life, and which u 

 from the two suhspiual chains in whoso formation nearly every pair of 

 nerves concurs, comport themselves in their distribution in a slightly 

 different manner. They are enlaced around arteries, forming on these 

 vessels very complicated plexifnrm networks, and yet the fibres composing 

 them are as absolutely independent as in the anastomoses above described. 



TEKMINATION OF THE NEHVES. This point should bo examined separately 

 in the case of the motor and the sensitive nerves : that is, in the muscles 

 and the integumentary membranes. The distinction, however, is not quite so 

 absolute as this, for the muscles always receive some sensitive tubes with 

 their motor filaments. 



In entering the muscles the motor nerves divide their branches, still 

 appearing as double-contoured tubes. It was at one time believed that these 

 fibres formed loops (Valentin) in the interior of the muscle, and returned 

 to their starting point. This opinion has become obsolete since the 

 ultimate termination of the nerves has been studied by Rouget, Krause, 



Fig. 894 



MUSCULAR FlISHKS, WITH Tl IK.M I NATION OF MOTOK NKUVK; KliOM TIIK 

 GASTROCNEMIU8 OF THK RANA KSCULKM \. 



, Terminal pencil of a dark -bordered nerve-fibre; l>, Intramuscular naked axis- 

 cylinder; c, Nucleus of the neurilemma ; d, Clavate extremities of the nervr ; 9. 

 Spaces of the muscle-nuclei ; /, Terminal knob of nerve, with central fibres and 

 vesicular dilatations of the nerve. 



Kiihne, Kolliker, Engelmann, Conheim (Beale), and others. What is known 

 of this subject is as follows : The voluminous, double-contoured nerve-tubes 

 which, more or less, cross the direction of the muscular fibres, soon divide 

 and form pale tubes on whose track are disseminated the nuclei. These; 

 tubes contain an axis-cylinder and a medullary layer. They pass on to a 

 muscular fibre in the following manner: the nucleated sheath of the IK iv< - 

 tube spreads, and is confounded with the sarcolemma ; the medulla suddenly 

 stops, and the axis-cylinder expands to form a minute granular mass named 

 the terminal motor-p'ate. Is this plate situated without or within tlr- 

 sarcolemma? This question is differently answered by histologists ; but, 



