On the laws of contagion, from a clinical standpoint.

Date:
[1891]
Catalogue details

Licence: Public Domain Mark

Credit: On the laws of contagion, from a clinical standpoint. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    3/16 (page 3)
    groups. Concerning the last, especially, it is, perhaps, desirable to add a few words of explanation. The results of modern discovery have tended to greatly widen our conceptions as to the sphere of parasitic elements in the production of disease. We are now scarcely able to think of contagion without at the same time calling up the image of a bacillus as its cause. It may be that in this direction we are going too far and too fast. At any rate, it will, I think, be admitted that it is desirable for the present to keep in mind the possibility that the tissues of the body itself may, without any parasitic addition, become themselves the causes of infective spreading. This I would submit is a possibility under most of the various conditions of disturbed nutrition, whether we name them new growths or inflammations. The phenomena of infective spread- ing in the case of Melanosis are very instructive. They are, by way of example, definite beyond the possibility of misconception. From one little pigmented mass a thousand just like it are produced, and are scattered in every part of the body. It would appear to be an example of contagion by cells, or, at any rate, by cell-forming plasma. There is- certainly no strong presumption that parasites have any share in it. What is here true of the infection-process is true also, with modifications, of all forms of malignant new growth, or, as we had perhaps better name them, malignant inflammations. Similar laws not improbably apply to other conditions, which, without any dispute, will be allowed to stand in the category of inflammations. I am thinking of boils, of acne, of contagious eczema, of psoriasis, lichen planus, and a multitude of other ailments in which the mode of spreading, multiplication, and also our methods of cure, favour the theory that they advance by the intervention of a contagious element. It may be that in many of these the contagious material is neither a bacillus, a psorosperm, nor a ptomaine, but a living cell, the product of the tissue whose nutrition has been disturbed. In connection with this important part of my subject I must ask attention to the important law that when once a focus of local inflammation has developed for itself peculiar and, so to speak, individual characters, it tends in all its subsequent stages of infection-spreading to keep to its type. This is illustrated in all the diseases which I have just named, and in many others. In order to explain it, we must resort, I think, to one of two hypotheses—either the inflammation has been produced by some specific contagion, or it has, in the course of its evolution, produced something equivalent to such. In order that I may illustrate what has just been said I will ask your attention to one of the very rarest of maladies; I allude to infective angioma of the skin. I show you two drawings, from different patients, which will, I think, convince all that this morbid process keeps to type. The two are exactly alike. I do not know of more than four examples of it