TISSUES OF THE BODY. 



323 



Fig. 311. A muscle fibre from the 

 lizard, a; b, nerve fibre; c, dichoto- 

 mous division in the terminal plate, 

 with transition into the true terminal 

 structure of Kiihne. 



formation, bounded by undulating lines and truncated processes. This is 

 the " true terminal plate" The nuclei and 

 finely granular substance of the "neural 

 eminence " are situated beneath this struc- 

 ture, adjacent to the fleshy mass of the 

 fibre (5). Engelmann also speaks of an ar- 

 borescent arrangement of branches of the 

 axis cylinder lying in the granular sub- 

 stance of the neural eminence. 



Now if, as would appear to be the case, 

 the distribution of the nerve fibre be 

 confined to the immediate mass of the 

 terminal plate, the extremities of the 

 muscle fibre must remain without nervous 

 supply, in that the former is set into the 

 latter at about its middle. But the fleshy 

 matter manifests contractility at the ex- 

 tremities also ! 



The bearing of the terminal portions 

 of the nerves supplying the muscles of 

 the lower orders of vertebrates, of naked 

 amphibia and fishes, present new difficulties in this so uncertain, but phy- 

 siologically so important subject. Here we find that those complex mul- 

 tinuclear terminal plates are no longer present. In the frog, the nerve 

 tube, on arriving at the fibre, not unfrequently breaks up into a multitude 

 of dark-edged fibrils, forming thus the " terminal tuft " of Kiilme. These 

 having pierced the sarkolemma, course along within the muscle fibre as 

 intra-muscular axis cylinders with isolated nuclei, and eventually become 

 merged, to all appearance, in the fleshy mass. Whether we have to deal 

 here with simple uninuclear terminal plates (Krause, Waldeyer) (of which, 

 in that case, several would seem to be present in one muscle fibre), or 

 whether this system of intramuscular axis cylinders may not represent in 

 the frog the true terminal plate of Krause, mentioned above, are questions 

 which must be determined by future research. 



According to Krause, these terminal plates are to be found also in the 

 heart of the rabbit. 



Taken from, other sources, the results which have been obtained on 

 inquiry into the nature of the final terminations of nerve fibres are 

 essentially different. 



REMARKS. 1. /. Mullcr and Briickc appear to have been the first who observed 

 division in the nerve fibres supplying muscle, in the year 1844. 2. Thus Reichert 

 counted 7-10 afferent nervous fibres in the thin platysma of the frog, containing 

 about 160-180 muscular fibres. These split up, eventually, with progressive rami- 

 fication, into 290-340 terminal filaments. 3. With regard to the final distribution of 

 nerves, modern literature is very rich. Compare, besides the works of Continental 

 investigators of Kiihne, Rouget, KoelliTcer, Engelmann, and others Beale (Proceed- 

 ings of the Royal Soc., vol x. p. 519 ; Phil. Transact, for the year 1861, p. 611 ; 

 and 1862, Pt 2, p. 889 ; also his Archives ofMed., No. 11, p. 257 ; and in the Quart. 

 Journ. of Micros. Science, 1863, p. 97 ; Proceedings, p. 302 ; and lastly (1864), 

 Transact., p. 94. 4. This is most beautifully seen in the group of small spider-like 

 animals, the tardigrades. Here, where many years ago the terminations of the 

 nerves, i.e., the neural eminence or terminal plate, had been recognised by Doyere, 

 the naked nerve fibre applies itself to the likewise membraneless muscle fibre, and 

 both masses become fused one into the other at the point of contact. If we now 

 suppose both nerve and muscle fibre enclosed in their sheaths, we obtain the same 

 relation of parts as in the mammal body. 5. According to Rouget, the neural 



