On the development of striated muscular fibre in Mammalia / by William S. Savory ; presented by James Paget.

  • Savory, William Scovell, 1826-1895.
Date:
[1855]
Catalogue details

Licence: Public Domain Mark

Credit: On the development of striated muscular fibre in Mammalia / by William S. Savory ; presented by James Paget. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    the appearance of a cylinder is produced, which becomes more perfect as the parti- tions between the cells disappear*. These observations have not been confirmed. M. Lebert has more recently studied the development of striated muscular fibre chiefly in the heart of the chick'f-. The following is a short abstract of his peculiar description of the process. “ The rhythmical contractions of this organ become very manifest and regular towards the thirty-sixth hour of incubation; nevertheless, it is at this time composed of nothing else than organo-plastic globules or elementary cells imbedded in a granular blas- tema. Between the fourth and fifth days of incubation are seen in the midst of the mass of globular particles certain elongated subcylindrical bodies, sometimes grouped together in a reticular manner; these bodies being the first rudiments of the muscular fibres, not merely in the heart but also in the other striated muscles, are designated by M. Lebert ‘ myogenic cells.’ Between the seventh and eighth days the 4 organo- plastic globules’ undergo a considerable diminution, and the muscular substance presents a more complete development. A longitudinal striation shows itself in the contents of the cylinders, which seems partly due to the grouping of the granular particles of which these contents consist; the transverse striations do not show them- selves until some time afterwards The organo-plastic globules which at first separated the primitive cylinders gradually disappear; the cylinders approach one another, and before the end of embryonic life they are found to be grouped into fasciculi;};.” When many months since I began to study the development of muscular fibre, it was with the hope of being able to add something to what appeared to be a very im- perfect explanation of the process. The results of these investigations I have endea- voured to communicate in this paper. It may be as well to state at once that the conclusions I have arrived at are, for the most part and in all important points, com- pletely at variance with the account which is generally believed to be the true one. I can therefore only meet the doubts with which I must expect the following state- ments to be received, with the assurance that they have not been hastily or carelessly advanced, and by an appeal to the verdict of future inquiry. These observations have been made for the most part upon foetal pigs, but they have been confirmed by repeated examinations of foetal calves, lambs, goats, rabbits, rats, and human embryos. In very small embryos, specimens of muscular tissue for microscopical examina- tion are most conveniently obtained from the dorsal region. If therefore a portion * Philosophical Transactions, 1840, 1841. f Annales des Sciences Nat. Juin 1849, Mars 1850. X Principles of Human Physiology, by Dr. Carpenter, 1853, pp. 305, 306. I have recently read a paper by Dr. Holst, giving a short account of some observations by Reichert and himself on the development of muscular fibre. From some of the engravings which accompany the paper, he has probably seen, although I think misinterpreted, the condition of the fibre in what I have described as the second and third stages of deve- lopment.