Report on the progress of human anatomy and physiology in the year 1844-5 / [Sir James Paget].

  • James Paget
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: Report on the progress of human anatomy and physiology in the year 1844-5 / [Sir James Paget]. Source: Wellcome Collection.

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    opaque condition. From these nuclear cavities are subsequently developed the minute radiated tubes (calcigerous canals). But these cavities are not formed in the layer of cement which covers the crown of the human and some other simple teeth ; the layer of capsule in which it is developed contains no nucleated cells. Growth of Parts. A series of micrometric observations has been made by Professor Harting,* with the view, chiefly, of determining the changes of number and dimension which the elements of each tissue and organ undergo in their development and growth from the early period of foetal life to adult age. His results show that the elements of the tissues may be thus placed in two classes : 1st, those elementary structures which, from their first existence to adult life, increase in size either very little or not at all; so that the growth of the tissue which they form must be ascribed to their multiplication, not their enlargement; and 2d, those which constantly increase in size, till the tissue or organ which they form has gained its full dimensions, while their number does not increase after birth; the growth of the whole organ depending on their enlargement, not on their multiplication. In the first class he places the cells of epithelia, the fibrils of fibro-cellular tissue and tendons, the primi¬ tive fibrils of voluntary muscles, the cellular cavities of bones, and the blood- corpuscles. In the second class are the cells of the black choroidal pigment, of the fat, and of the liver, the primitive fasciculi (fibres) of voluntary muscles, and the fibres of involuntary muscle, the primitive nerve-tubules, the cells of cartilage, the urine-tubes and Malpighian capsules ; and, probably, the fibres of elastic tissue and the ganglion-corpuscles. In a third class he says we might place a few elementary structures the number of which appears even to decrease after birth, e. g. the primitive fibres of muscles and the cells of permanent cartilage. STRUCTURE AND FUNCTIONS OF THE URINARY ORGANS. The Structure of the Kidney has been studied by Drs. Gerlach,f Bidder,]; and Kolliker,§ who all confirm the description of Mr. Bowman in nearly every particular—only they all find that the Malpighian body or tuft of vessels does not lie naked or bare within the capsule. The first two describe it as covered by a layer of epithelium, reflected on it from the walls of the capsule, like the reflected or visceral layer of a serous membrane; and they admit a space exist¬ ing between this reflected layer of epithelium and that by which the capsule is lined. Kolliker thinks there is no such space, but that the Malpighian body is imbedded in one continuous layer of epithelium, which on the one side covers and fits into all the spaces between its vessels, and on the other is attached to the structureless membrane which forms the wall of the capsule. Gerlach also says that the Malpighian capsules (which he has examined in the injected kidneys of sheep) are not at the ends of the tubules, but are attached like diverticula to their sides—[but they are certainly terminal in the human kidney; and Bidder and Kolliker assert that they are so in the kidneys of the frog and the triton : they may be lateral in the sheep; but it is more probable that they only appear so when two tubules lead to one capsule. Whenever this happens, as it does sometimes in other than sheep’s kidneys, the capsule which is really at the junction of the ends of two tubes may appear like a lateral diverticulum on one]. Gerlach, moreover, holds (as Valentin does) that the ciliary epithelium in the frog’s kidney extends over the whole internal surface of the capsule; but neither Kolliker nor Bidder agrees to this. Kolliker’s observations were made in connexion with others on the primor¬ dial kidneys or Wolffian bodies, the structure of which he has found to be * Recherches micromctriques, 4to; Utrecht, 1845. t Miiller’s Archiv, Heft iv, p. 3/8. j Ibid. Heft v, p. 508. § Ibid. Heft v, p. 518.