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Cited by W.H. Howell and G.C. Huber, 'A Physiological, Histological and Clinical Study of the Degeneration and Regeneration in Peripheral Nerve Fibres', Journal of Physiology 13 (5) (1892), pp. 335-406
Tags: haemotoxylin, osmic acid, picric acid, gold
Description:Explanation of Plate XVI (figs. 56-69):
Figs. 56, 57, 58, 59. From nerve stained in picric acid atid haematoxylin. Exp. XIX. 7 weeks. R. S. J in. below wound. 59. An embryonic fibre. 58. Newly-formed fibres with myeline and axis. 57 and 56. Newly forming fibres, myeline as a varicose tube. Axis also present but not stained in the interior of the swellings of myeline. Shows how quickly after the formation of the myeline the axis grows down from above.
Fig. 60. To show the branching of the axis cylinder where an old fibre passes into several new fibres, central end of ulnar. Exp. XXlI. Cut for 75 days and union with peripheral end prevented. Picric acid and haematoxylin.
Fig. 61. To show what seems to be the outgrowth of an axis cylinder from an old fibre toward a new one. New myeline lies in the embryonic fibre as a continuous delicate sheath. Exp. XVII. 4 weeks. R. S. Gold and haematoxyiin.
Fig. 62. To show the formation of several new fibres in the degenerated portion of a single old fibre at the central end of wound. Exp. XVII. 4 weeks. L. S. wound of median ulnar suture. Osmic acid and haematoxylin.
Fig. 63. The sanme. Human ulnar nerve. Central end of nerve 6 1/2 months after injury. No union with peripheral end. Gold and haematoxylin.
Fig. 64. To show junction of old with new fibre at the central end. Exp. XVIII. R. S. wound. Osmic acid and haematoxylin.
Fig. 65. The same. Human ulnar. Central end 6 1/2 months after section and no union with peripheral end. The continuation of the protoplasm of the "embryonic fibre" into the hypertrophied protoplasm surrounding the nuclei of the old fibre, and the fragmentation of the end of the old myeline to be specially noted. Gold and haematoxylin.
Fig. 66. To show junction of old and new fibres, and the new fibre with its thin myeline sheath lying in the protoplasm of the "embryonic fibre." Exp. XVII. R. S. wound. Gold and haematoxylin.
Fig. 67. To show junction of old and new fibres. Central end of human ulnar, 6 1/2 months after injury and no union with peripheral end. The fragmentation of the myeline and the hypertrophy of the protoplasm round the nuclei of the old fibre to be noted. Gold and haematoxylin.
Fig. 68. The same.
Fig. 69. Cross-section through the bulbous enlargement of central end of human ulnar, 6 1/2 months after injury and no union with central end. Shows the increase in the endoneural connective tissue as well as in the nerve fibres. The fibre marked + shows cross section of new fibres in same sheath with old. Compare with figs. 63, 65.' (405-406)
Figs. 56-57 in text:
'when the new myeline is evidently just formed no definite axis can be demonstrated by the gold stain. With the picric acid and haematoxylin stain, on the contrary, the newly formed axis is clearly seen, even at that early stage in the formation of the myeline tube when it exists as a string of bead-like swellings (see Figs. 56 and 57). It follows then that though the myeline sheath probably begins to form before the axis cylinder can be distinguished, the latter appears shortly afterward, before the new fibre has gone far in its development.' (380-381)
Fig. 61 in text:
'Very many apparent examples of this branching of the axis were found in this specimen, but owing, to the intricate way in which the fibres were twisted and the possibilities of deception arising therefrom, the connection of the old and new axes could not be satisfactorily followed. The example given in the drawing, and some others, were, however, quite distinct and seem to us to give fairly satisfactory histological proof that in regeneration the new axis cylinders are outgrowths from the axes of the uninjured fibres of the cenitral end. Fig. 61 gives an apparent example from another experiment of the outgrowth of the axis.' (382)
Figs. 62-69 in text:
'We have not followed all the stages of degeneration and regeneration in the central end with the same care as in the peripheral end; but the stages we have examined have convinced us that the processes are practically identical in the two ends. The myeline and axis disintegrate and are absorbed for a certain distance; an embryonic fibre is formed from the new protoplasm arising from the nuclei, and in this a myeline sheath is first formed into which an axis cylinder penetrates as an outgrowth from the end of the old axis. Various examnples of this formation of a new fibre within the sheath of the old are shown in Figs. 62 to 72. In many cases, in the central end, when union was not made or when difficult union was made as in cross sutures, an old fibre was found to terminate in a bunch of two or more new fibres (see Figs. 62 and 63), usually coiled round one another so that they could not be disentangled.' (382)
Figs. 63, 65 and 67 in text:
'Still another interesting fact is shown by the teased preparations of the central end of the same nerve, and that is, that the degenerative changes in the central end, when union is not made, apparently keep on progressing centripetally at a slow rate. Figs. 63, 65 and 67 give good illustrations of this fact.' (383)
Figs. 63-65 and 69 in text:
'Cross sections of the central stump of the human ulnar nerve operated upon by Dr Mc Graw for secondary suture, six and a-half months after injury, confirmed the results which were obtained by teasing (see Fig. 69). The section was rnade through the bulbous enlargement of the central stump. At the level of the section no normal medullated fibres were found, though occasionally a cross section of a smaller fibre with some remnant of the axis was seen. In other places a bundle of small fibres was found of the same area as one of these enlarged fibres, and at still other spots intermediate stages were seen showing an enlarged fibre surrounded by small new fibres in the same sheath. In this case the bulbous enlargement was undoubtedly caused by an increase in the nerve fibres as well as in the epineural connective tissue. If the cross section described is compared with the teased preparations, Figs. 63, 64, 65, made from the central end of the same nerve the way in which an old fibre makes connection with a bundle of new fibres lying in the same sheath will be more readily understood. One can understand from the teased preparations how in the cross section a portion of the myeline of an old fibre may be obtained surrounded by a number of newly-formed fibres in the same sheath. ' (383)
Figs. 64 and 65 in text:
'Similar preparations were obtained from the central end of the ulnar, in a dog, which had been severed 75 days before the examination was made, and had not been allowed to unite with the peripheral end. In some of the specimens from this latter nerve the mode of union of the axis cylinder in the newly regenerated fibre with the axis in the old fibre is clearly shown (Figs. 70, 71, and 72). Fig. 71 is particularly instructive when compared with Figs. 64 and 65. The new axis cylinder is seen to escape the swollen end of the old fibre and to penetrate the inyeline some distance beyond this point in order to reach the old axis. Fig. 72 shows the end of an old axis cylinder enlarged and sending out a new axis.' (383-384)