The Erasmus Wilson lectures on the general pathology of tumours : delivered before the Royal College of Surgeons of England on February 10th, 12th, and 14th, 1902 / by Charles Powell White.

  • White, Charles Powell, 1867-1930.
Date:
[1902]
Catalogue details

Licence: In copyright

Credit: The Erasmus Wilson lectures on the general pathology of tumours : delivered before the Royal College of Surgeons of England on February 10th, 12th, and 14th, 1902 / by Charles Powell White. 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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    or destruction, any proliferation which subsequently takes place being compensatory in nature to replace the cells which have been destroyed, I am not convinced that the prolifera- tion of epithelial cells in coccidiosis is primary—that is, that the parasite directly causes proliferation. Even if a parasite were capable of causing a primary proliferation it would not explain the occurrence of a carcinoma since the essential lesion of carcinoma is not proliferation but is penetration of the epithelial cells into the connective tissue. In the next place, the reaction of the organism against all known parasites, animal and vegetable, is of a defensive nature and characterised by the phenomena of inflammation. The parasite first gives rise to injury or destruction of the tissues : this is followed by exudation of leucocytes which remove the damaged tissue and, if possible, the parasite, and this again by proliferation of the surrounding tissue which repairs the injury. A tuberculous nodule, for instance, is formed by centripetal proliferation of the surrounding tissue— that is, by proliferation taking place towards the irritant. It is far otherwise in carcinoma ; here we have pro- liferation taking place in a centrifugal direction away from the supposed parasite and, instead of a defensive reaction, there is produced an ever-increasing amount of epithelial tissue in which the ' parasite can grow and multiply. In fact, the organism would seem to welcome the parasite instead of repelling it. This is so opposed to the accepted laws of parasitism that one may be excused for doubting its possibility. Some have supposed that the parasite acts on the cell in somewhat the same way as a sperm cell acts on a germ cell and thus induces proliferation. This seems to me a very far-fetched and un- warrantable supposition and is negatived by the fact that, as regards the parasites that have been described, the parasite- containing cell does not undergo division. To make sure of this fact, which was mentioned by Ruffer and Plimmer,21 I recently wrote to Mr. Plimmer and he tells me that the cells which contain the inclusion do not divide, but, as a rule, begin to show degenerative changes similar to those in phagocytic cells in other diseases when the cells cannot conquer. These degenerative changes would, however, seem to be very slight in amount. As regards the relation between the supposed parasite and the cell, we have to consider how the parasite, in the case of intracellular parasites, enters the cell. Is the entrance active on the part of the parasite or passive as in phago- cytosis ? or does the parasite fulfil its whole cycle within the cell? The last supposition is impossible, for, since the containing cell does not divide, the parasite would not have any opportunity of continuing its existence when the cell had degenerated. If the entrance is an active process on the part of the parasite it is difficult to understand how a 21 Journal of Pathology and Bacteiiology, vol. i.