The infectivity of cancer : a retrospect and a forecast / by D'Arcy Power.

  • D'Arcy Power
Date:
[1895?]
Catalogue details

Licence: Public Domain Mark

Credit: The infectivity of cancer : a retrospect and a forecast / by D'Arcy Power. Source: Wellcome Collection.

    4/12 (page 2)
    1 propose in this paper to shortly review these two chains of evidence; and as it raises several points in which practi¬ tioners in the Thames Valley can help me, I asked your secre¬ tary and my friend, Mr. Lewis Morgan, if I might read my paper in the Oxford district. The scientific evidence is mainly experimental, partly de¬ rived from the histological examination of cancerous and other tissues, and partly from the results of the inoculation or grafting of cancer upon men and animals. Much of the evidence based upon the interpretation of minute histological appearances is to my mind invalidated by the fact that the majority of observers have confined their attention to the examination of cancerous tissues, and have not taken the trouble to compare the results thus obtained with those seen in similar tissues only slightly removed from the normal. This method of examination has been carried so far that in some cases the examination of a single tumour has been thought to afford sufficient evidence upon which to base an entire theory. Unusual appearances, due either to faulty methods of preparation or to changes in the cells themselves, have been said to be protozoa without any attempt to prove that they were so, whilst the bare statement of one observer has been accepted by another who has employed it to elaborate and father a theory of his own. There is, however, a single redeeming feature in this mass of crude hypothesis, for each observer has drawn to the best of his ability what he has seen, and we thus possess a large and often splendidly- executed series of plates to illustrate the minute appearances in the epithelial cells of cancer. Nothing is perhaps more re¬ markable than the manner in which each investigator has felt his inability to describe in words these appearances ; in no branch of pathology has the skill of the lithographer, the photographer, and the engraver been called in with such signal success as in this inquiry into the cause of cancer. We shall owe the solution of the riddle in all probability to these pictures and to those which are yet to be published, for there is no likelihood of a speedy conclusion to our labours. The appearances are for the most part as varied as the nationality of the observers. A few only can be traced, even in their broadest outlines, through the whole series, and many of those which appear to be common to all varieties of cancer are also met with in epithelial cells which have not been obtained from carcinomatous tissues. The appearances common to the largest number of observers are, as might have been expected, the simplest. They are tiny circular bodies, varying in size, but many times smaller than red blood corpuscles, found either singly or in groups, sometimes inside the cells and sometimes lying between them. The explanation of these bodies has yet to be obtained, but I here show you photographs of them. You will see that some of them are intracellular whilst others lie between the cells, and you will also notice that they vary in size. It may be that such bodies are the result of some cellular change of which we are ignorant; it may be that they are peculiar to the epithelial cell endowed with those characters which render it cancerous. We have as yet no evidence that they are protozoa, we have still less reason to say that they are a cause of cancer. We can only state for the present that