Recent advances in the physiology of motion, the senses, generation, and development. Being a supplement to the second volume of Professor Muller's "Elements of physiology". / by William Baly and William Senhouse Kirkes.
- Date:
- 1848
Licence: Public Domain Mark
Credit: Recent advances in the physiology of motion, the senses, generation, and development. Being a supplement to the second volume of Professor Muller's "Elements of physiology". / by William Baly and William Senhouse Kirkes. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![TRANSFORMATIONS UNDERGONE BY NUCLEI. Batrachians, a complete network of nerve-tubes is formed by this junction and coalescence of the processes from branching cells: a similar observa- tion was also made by Schwann.* * * § According to Schaffner, as the nerve- tubules coalesce and increase in size, the walls of the cells from which they originate are gradually drawn out and merge into those ol the tubules, while their granular contents also become continuous and identified with the contents of the tubules. In considering the transformation which cells undergo in the develop- ment of tissues, too much stress cannot be laid on the importance of the share taken by the nuclei in these changes, especially since this appears to have been entirely overlooked by Schwann. It is proposed, therefore, to bring together some of the more striking circumstances which seem to demonstrate the importance of nuclei, whether considered as individual structures, or as component parts of cells. That the nuclei may exist in tissues apparently independent of cells, has been shewn especially by the observations of Mr. Paget,f who found that many morbid growths are composed almost entirely of corpuscles like nuclei or cytoblasts. These morbid structures were usually tumours of very rapid growth, and from the almost invariable presence of large quantities of nuclei, it would seem that they must play an important, if not the chief part in this growth. The abundance of nuclei in most, if not all, other actively grow- ing tissues, healthy as well as morbid, their persistence in those tissues, such as the muscular, in which a constant waste and repair consequent on the active discharge of their function is taking place, their invariable existence in the secreting cells of all glands and epithelia, and their disappearance from the cells of fat, which when fully formed cease to perform any active function, all attest the importance of the share taken by the nuclei in the processes of growth, reproduction, and secretion. Equally strong confirmation of this is furnished also by the variety of examples in which development, in either structure or composition, is effected in the animal organism by cells unprovided with nuclei, while there are many instances in which nuclei, whether contained in cells or without them, appear to assume higher forms, or to be centres and sources of formative and reproductive power.]; The evidence of these facts is based chiefly on his own observations on tumours above alluded to, and on the investigations of Professors IIenle§ and Goodsir,|| and of Mr. Simon.If The researches of the last-named observer on the glands without ducts, tend to prove the discharge of a large amount of gland-function by nuclei alone; for in the thymus, the splen, and other such glandular organs, * Mikroscopische Untersuchungen, p. 177. + Report on Anatomy and Physiology for 1844-5, p. 35. + Mr. Paget, Lectures at the Royal College of Surgeons, May 1847. Lecture 5. § Allg. Anat. pp. 192—9. II Anatomical and Pathological Observations, 1845. % A Physiological Essay on the Thymus Gland, 1845.](https://iiif.wellcomecollection.org/image/b21967660_0139.jp2/full/800%2C/0/default.jpg)
