Dawson, James, Walker

2018-09-13T16:06:09Z

2018-09-13T16:06:09Z

1907

I approach this part of my work with more than reluctance. My inexperience in the interpretation of pathological processes, and the incomplete stage which my work has yet reached, give me no warrant to summarize conclusions on a subject beset with so many difficulties. It is customary, however, to end a thesis with a few such remarks. The conclusions to be -stated have been gathered from the impressions derived from the direct observation of morphological facts. Sections have been cut from over 140 blocks of tissues representing the processes of inflammation and repair; between 700 and 800 specimens have been stained. The almost insurmountable difficulty experienced in cutting these sections thin enough for the examination with very high powers has left little time for their systematic study, and I am quite prepared on closer observation to modify or withdraw the statements I now make.

The primary object, however, of this paper was to present, as briefly as is consistent with clearness, a consecutive view of the chief problems in relation to wound- healing. An endeavour has been made to state the various theories which have been offered for their solution.

A study of the histology of woundhealing impresses one with the view that each factor in the inflammatory process not only tends in one direction and that a aparatiire one, but also that each reaction is purposeful. Here and there I have tried to point this out and I lay stress upon it now as perhaps the one general broad impression that forces itself upon one. Adarai has stated that if we recognize physiological purpose, we must admit pathological.

Chemiotaxis is retarded by many as a convenient term to explain much that we do not understand. It maybe so, but however much is included in it, it plays a very important part in _the phenomena of inflammation. The chemiotaotic influence exerted on all living pr. otoplasm accounts for many of the processes we could not otherwise explain, and is, I think, largely accountable also for the cell-proliferation.

Regarding the various problems, a much deeper study than I have yet been able to give my specimens is necessary before I am justified in coming to any conclusions, other than those gathered from reading.

The vexed question of the haematogenous or histogenous origin of the mononucleated cells seems about to be solved by finding a via media between the two main opposing views. This reconciliation has found its chief advocate in Adami. The points at issue will further be much simplified if other workers bear out Maximow' s confident assertions in many passages, -regarding the young fibroblasts which arise from the mitotic division of the connective- tissue cells. These, Maximow arie states, can be immediately recognized as such, and not similar to the small round cells found in such large numbers during the early stages of inflammation. Almost all other authors hold that young connective -tissue cells are small round cells indistinguishable from the other round cells of the inflammatory exudate. Maximow bases his statements on the character of the nucleus and nucleolus, and the structure of the protoplasm. I think that my specimens bear this out but it is an important point requiring prolonged study and I am not convinced.

If Maximow is correct ecit certainly clears away many difficulties. In the inflamed area we would find three distinct types of. cells:-

(1) Leucocytes - with a definite origin. (2) Mononucleated cells - with a very varied origin. (3) Fibroblasts - with a definite origin.

Can these cells be kept apart with a definite function of their own, and be immediately recognisable as such cells in the inflamed area? Or are fibroblasts, at one stage of their career similar to mononucleated cells? And, if so, which of these many mononucleated cells, acknowledged to have a very varied origin, spring from the pre -existing connective- tissue cells? Lastly, do any of the others give rise to cells forming fibrous tissue?

An eradication of the problems regarding the origin of the so- called "histogenous wandering cells" would also do very much to clear the ground.

I think most writers have taken far too little account of the cells coming to the inflamed area in the lymph-stream. The bone marrow has been shown to be a readily available source of leucocytes in case of need. The lymph-glands in the neighbourhood of an inflamed area and Ribbert's lymphoid nodules where present must surely also present a readily available supply in emergency .

Plates V.and VI. beautifully illustrate fibril formation and new vessel- formation. I have. not yet succeeded in overcoming the difficulty of getting serial sections of skin tissues, and without these I cannot come to any decision on the mode of format ion of the new vessels.

The Plasma -cell question is also important. From the study of my specimens, especially of abscess walls, I am convinced that this is a specially differentiated cell with a specific function. What this function is, and how it is carried out, are not decided. It may be that some substance is produced which reaches the circulation, having an influence general and local on abscesses, granulomata, and tumours.

http://hdl.handle.net/1842/32686

The University of Edinburgh

Annexe Thesis Digitisation Project 2018 Block 20

Some problems in relation to the healing of wounds

Some problems in relation to the healing of wounds: Syme Surgical fellowship, 1907

Thesis or Dissertation

Doctoral

Prize Essay