Licence: Public Domain Mark
Credit: Surgery. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![round cells and ()c-cii])\- the space which was formed by the removal of the damaged tissues by the emigrated leucocytes. In this mass of cells vessels are formed, probably for the most part by the budding out from the endo- thelial cells of adjacent cajMllaries : these buds become joined with others arising from capillaries in the neighbourhood and, becoming hollowed out, form new vessels. In this way a new tissue has been formed, which is known under the name of granulation tissue. This name is given to it because its structure is of the same elementary character as that of the granulations on the surface of a healing ulcer. It consists simply of cells adhering to each other—i.e. embedded in an apparently homogeneous matrix amongst which ramify innumerable thin-walled capillaries. The cells of the tissue are for the most part round, especially if an examination be made at a very early stage, but they have, under certain conditions, a tendency to become spindle-shaped and elongated, so that it is seldom the case in examining granulation tissue that nothing but round cells are found : there are often seen also spindle-shaped cells, fibre cells, and immature fibrous tissue. The granulation tissue, thus formed from the fixed connective tissue cells of the part, may undergo one of two changes : it may either undergo a developmental change or a degenerative change. Which of these changes it undergoes would appear to depend mainly upon the amount of nutritive supply afforded to it, for in the same mass of tissue we may see the two changes going on contemporaneously. In the centre of the mass, at the point furthest removed from the source of nutrition, degenera- tive changes will be seen taking place; whilst at the periphery, where more nutrition can be supplied by adjacent blood-vessels, developmental changes will be found to be going on. I. The developmental change is sometimes termed i-etrogression^ be- cause it consists in the formation of a new material, of a less complex nature than the original tissue which it replaces. The character of the new material varies to a certain extent, but it belongs to the connective tissue type and assumes the characters of the connective tissue in which it is formed. Thus if the inflammation has been in bone, of which a portion has been removed by the inflammatory process and its place occupied by granula- tion tissue, this tissue eventually ultimately undergoes a development into bone. So, again, if the tissue inflamed has been fibrous tissue, the new material formed from the granulation tissue becomes dense fibrous tissue. But it must be borne in mind that where the more complex tissues, such as muscle, cartilage, skin, are destroyed, they are never restored, but the granulation tissue which is formed in these cases becomes converted into new fibrous tissue. This new material which arises from the develop- mental process which goes on in granulation tissue is known as ' scar ' tissue : it will be considered more in detail in connection with the subject of the union of wounds, where the gradual developmental processes which it goes through, and its structure, can most conveniently be studied. It will be sufficient in this place to say that the process in all probability consists in the elongation of the round cells of which the granulation tissue in the first place consists. The cells first become spindle-shaped : then they become more elongated and assume the form of fibre cells, and eventually form the fibres of fibrous tissue, which become bound together by an interstitial homogeneous cement substance. Thus a new fibrous tissue is formed, which may undergo further changes accord- ing to the nature of the connective tissue in which it is formed. Thus, in c](https://iiif.wellcomecollection.org/image/b21210846_0043.jp2/full/800%2C/0/default.jpg)
