Anat. Anz., 1902.. M. Heidenhain's und mein Auffassung der kontraktilen und leitenden Barker, L. F. The Nervous System and Its Constituent Neurones. Bethe, A. New York, 1899. Eine neue Methode der Methylenblaufixation. Anat. Anz., 1896, Bd. 12, Die anatomischen Elemente des Nervensystems und ihre physiologische Cuccati. Delle terminazioni nervee nei muscoli addominali della Rana temporaria e della Rana esculenta. Internat. Monatsh. f. Anat. u. Phys., 1888, V. Dogiel, A. S. Methylenblautinction der motorischen Nervenendigungen in den Muskeln der Amphibien und Reptilien. Arch. f. mikr. Anat., 1890, XXXV. Ehrlich, P. Ueber die Methylenblaureaktion der lebenden Nervensubstanz. Biolog. Ueber die Beziehungen von chemischer Konstitution, Verteilung und Gerlach. Ueber die Einwirkung des Methylenblaus auf die Muskelnerven des lebenden Froschen. Sitzber. d. math.-phys. Cl. d. k. bayer. Akad. d. Grabower. Wiss., 1889, XIX. Ueber Nervendigungen im menschlichen Muskel. Arch. f. mikr. Anat. u. Kühne. Ueber die peripherischen Endorgane der motorischen Nerven. Leipzig, 1862. Krause. Uber die Endigung der Muskelnerven. Arch. f. rat. Med., 1863. Also several papers in the earlier numbers of the Internat. Monatsh. f. Anat. u. Phys. Huber-DeWitt. A Contribution on the Motor Nerve-endings and on the Nerve-endings in the Muscle-spindles. J. Comp. Neur., 1897, v. 7, 169-230. Perroncito, A. Sur la terminaison des nerfs dans les fibres musculaires striées. Arch.. Ruffini, A., and Apathy, St. Sulle fibrille nervose ultraterminali nelle piastre motrici dell' uomo.. Ruffini, A. Le fibrille nervose ultraterminali 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 über die Nerven der Muskeln mit besonderer The Nerves of the Capillaries, with Remarks on Nerve Endings in Mus- 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. 1. ZEISS D, Comp. occ. 4. The peripheral termination of a neurone, showing Terminal fibrillae with end knobs (1) 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 outlined surrounding the continuous and well-marked axis-cylinder. There are three 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 medullary 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 intefmuscular connective tissue. The main supply of B is b; 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. 1, 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 (1), shows the fibrillae breaking up into a granular netlike 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. Fig. 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 (1). It gives off at (2) a large non-medullated 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 represented. Several of these endings showed knobs similar to those repre sented in Fig. 1, B and C. A separate non-medullated nerve (n) is shown which forms a small plexus on B, one fiber of which penetrates to a lower plane than the others and ends by forming under the sarcolemma a knob like Fig. 1, B; the other fibers pass on, one to end on B, the other on C. Fig. 3. ZEISS D, Comp. occ. 4. Three medullated nerves (a), (b) and (c), which pass to three separate muscle fibers, A, B and C, and which have ultraterminal fibrillae and interlacing of endings. Muscle fiber B is seen only in part. Fig. 4. ZEISS D, Comp. occ. 4. The type of ultraterminal fibrillae seen most frequently. Fig. 5. A. ZEISS D. Comp. occ. 4. An ending forming a complex network on muscle fiber C. A nerve coiling round the primary terminal divisions of another nerve (compare page 11 on relation of nerve to sarcolemma). The nerve n goes to two muscle fibers, A and C. The nerve 3 on which no medullary sheath was seen divides into two branches; one of these ends undivided, the other separates into two branches which run close together and parallel. At (2) the upper branch coils round a primary fibril of the nerve ending on muscle fiber A; in addition it gives off a fibril which disappears in adjoining connective tissues. Fig. 5, B. Part of Fig. 5, marked (1), drawn with ZEISS oil immersion 1-12 Comp. occ. 4. PLATE II. Fig. 6. ZEISS 1-12 oil immersion, Comp. occ. 4. Sections cut 10 μ. Nerve endings shown only in part, with ultraterminal fibrillae (1), (2) and (3), one of these (1) with sheath. The main fiber is seen at n. From it a branch to the right passes off and soon divides; one of these divisions has been cut by the sectioning, the other (1) passes to an adjoining muscle fiber, there to end in a small termination like an end-plate with end knobs. The nerve sheath could only be traced distinctly to the point where the nerve enters into contact with the muscle fiber. Fig. 7. ZEISS 1-12 oil immersion, Comp. occ. 4. Section 5 μ. Stained in orange G, acid fuchsin. Part of nerve ending lying over sarcolemma. This dye colors the sheath of HENLE rose-pink, the neurilemma pink, and the muscle fiber orange. The medullary sheath was apparent at M just above the node R, where the axis-cylinder divides into three branches which pass to the muscle fiber. The sheath of HENLE (H) is seen continued over R wituout attachment, and two of its nuclei (Hn) were distinctly outlined. Within the sheath of HENLE and closely applied to the axis-cylinder, lay the neurilemma N, attached to the node R. The primary terminal fibrils surrounded by the sheaths lie over the sarcolemma which is distinctly marked beneath the sheath. Fig. 8. ZEISS apochomatic 1.5, Comp. occ. 6. Section 7.5 μ. A primary terminal fibril with sheaths. H, HENLE'S sheath; N, neurilemma; S, sarcolemma. Section 5u. A terminal Fig. 9. ZEISS apochromatic 1.5, Comp. occ. 6. knob lying under the sarcolemma and covered by a cap which is chiefly composed of the nerve sheath. Fine fibers pass at (a) and (b) from the sarcolemma to blend with the nerve sheath in the cap. |