Wilson, Motor Endings of the Frog. 15. 



Ruffini, A. 



Le fibrille nervosa ultraterniinali nelle terminazioni nervose di senso e la 

 teoria del neurone. Riv. di Pat. nerv. e ment., 1900, v, 6, 70-82. 

 Sihler, Chr. 



Neue Untersuchungen iiber die Nerven der Muskeln mit besonderer 

 Beriicksichtigung umstrittener Fragen. Zeit. f. 7uiss. ZooL, 1900, 

 LXVIII, 3, pp. 323-378. 



The Nerves of the Capillaries, with Remarks on Nerve Endings in Mus- 

 cle. Journ. of Experimental Medicine, 1901, vol. 5. 



EXPLANATION OF THE DRAWINGS. 



I am much indebted to Mr Leonard H. Wilder for the carefulness and 

 accuracy with which he has prepared the drawings which illustrate this paper. 



PLATE I. 



Fig. I. Zeiss D, Comp. occ. 4. The peripheral termination of a neurone, 

 showing Terminal fibrillae with end knobs (i) and (2), Ultraterminal fibrilla 

 ending in intermuscular connective tissue (3), Ultraterminal fibrilla ending 

 on a separate muscle fiber (4). 



The medullary sheath, as sometimes happens, is faintly yet distinctly out- 

 lined surrounding the continuous and well-marked axis-cylinder. There are 

 thre^ muscle fibers, A, B and C, to which go two medullated nerves, a and b. 

 The main stem of a breaks up on C at 5 into three primary fibrils. In its 

 course there are given off to A two medullated branches, which lose their me- 

 dullary sheath soon after leaving the main stem and which break up more or 

 less dichotomously. From the one on the left, a non-medullated terminal branch 

 (3) passes beyond the muscle fiber to disappear in the intermuscular connective 

 tissue. The main supply of B is <5 ; but the medullated nerve, a, while passing 

 over B gives off two very fine, apparently non-medullated branches, one of which 

 ends on B, the other passing to end on C. The termination of the medullary 

 sheath of a was close to the breaking up of the axis-cylinder at 5. One of the 

 primary terminal branches on the right gives off a branch 4 which divides 

 dichotomously on muscle fiber B. The others call for no special remark. 



Fig. J, B and C. Zeiss 1-12 oil immersion ; Comp. occ. 4. Two forms of 

 endings frequently presented at the terminals of very fine fibrillae. 



B, Drawn from (i), shows the fibrillae breaking up into a granular net- 

 like structure. 



C. Drawn from (2), shows an elongated broadened club-like body with a 

 marked central axis, imbedded in a well-defined granular mass and surrounded 

 by a homogenous capsule, comparable to cap seen in Fig. 9. 



Fii;. 2. Zeiss D, Comp. occ. 4. Nerve ending with ultra-terminal 

 fibrillae. 



The medullated nerve a loses its medullary sheath and breaks up on B at 

 (i). It gives off at (2) a large non-meduUatcd branch which also breaks up on 

 B. The nerve endings send ultraterminal fibrillae to three muscle fibers. The 

 terminal branches to the right could be traced to a distance twice as far as rep- 

 resented. Several of these endings showed knobs similar to those repre- 



