ARRANGEMENT OF THE NERVE FIBRES. 



205 



profile view ; at e, we see the structure from its broad 

 external surface. Its size varies between 0.0399 to 0.0602 

 mm. ; the number of the nuclei from 4 to 20. 



The great delicacy and changeableness of the motory ter- 

 minal plate impedes its further study considerably. Does the 

 axis cylinder actually cease on spreading out into the former? 

 Or, does the termination of the axis cylinder first occur in the 

 interior of the terminal plate, so that the signification of some- 

 thing like a cushion is to be ascribed to the latter? 



In the muscular filament of the lizard (Fig. 179) we obtain, 

 under certain circumstances, a peculiar interesting appearance. 

 In penetrating the terminal plate, the axis cylinder of the nerve 

 fibre {b, c) divides and, rapidly 

 losing its medulla, passes over by a 

 continual ramification into a pale, 

 obtusely branched, antler-like fig- 

 ure (d,d). The molecular nucleated 

 substance is just beneath this ex- 

 pansion. We are indebted to 

 Kuehne for this observation. I 

 have seen something similar by 

 reexamination ; but we are once 

 more at the limits of the present 

 microscopy. Kuehne named this 

 antler-like formation the true ter- 

 minal plate. 



This is, according to our expe- 

 rience, the present state of the 



matter. Others maintain deviating views, as most recently 

 Arndt and Gehrlach. It is impossible for us to enter here 

 into a polemic, the more so as this lies at the limits of the 

 present microscopic perception. 



Concerning the nerve termination in the muscles of the 

 heart, only hypotheses exist at present. 



We have also no very satisfactory knowledge of the nerves 

 of the smooth muscles. 



Many years ago various observers (Beale, Arnold, His, 



Fig. 179. — Muscular filament (a) of 

 the lizard ; b, nerve fibre ; c, its branches 

 with the peculiar terminal figure, d. 



