Selected monographs on dermatology / [Paul Gerson] Unna [and others].

Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Selected monographs on dermatology / [Paul Gerson] Unna [and others]. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    of tlie whole vascular tree—the vascular pores being dimin- ished. and the outbreak of luflammation thus made more diffi- cult. The thickening of the walls of the valved arterial - branches of the frog’s web, as described of Klemensiewicz, when the blood-pressure is falling, offers an acceptable physio- logical parallel. In the really organic diminution of calibre of the cutaneous vessels, the capillaries, many of the arterioles and venules, and some few larger branches, are actually converted into cellular or fibrous connective tissue. Embolism and throm- bosis, as causes of anaemia, play an important role in dermal pathology; but on account of the very frequent anastomosis of the cutaneous vessels, only infective embolisms have serious results. Innocent emboli, indeed, may be carried and lodged in the cutaneous network without producing symptoms, and the same is true for local thrombosis following such emboli. Careful search would no doubt reveal them, in cases of general embolism, to be much more frequent in the skin than is com- monly supposed. We often find, quite unexpectedly, in the examination of tumours, thrombi of apparently harmless bac- teria, of secondary importation, or hyaline thrombi in wider areas, the former being too small, and the latter allowing the blood-stream too much room, to produce any perceptible anemia, although they must obviously increase the resist- ance to the blood entering the capillary area. For the production of real anaBmia, there only remains a narrowing of the capillary region, leading to obliteration of lumen by young connective tissue. The process called endo- arteritis obliterans by Eriedlander, is of much greater im- portance in the pathology of the skin than we might suppose. This fibrous vascular degeneration does for the skin, what the embolic and thrombotic closure of the vessels does for other organs in producing anaemia. A review of the dis- eases of the skin will show that it may follow infective in- fiammations as well as ulcerative processes, and progressive as well as retrogressive disturbances of nutrition. Without enumerating all the individual instances, we may poiiit out the general characteristics ; and for this purpose it seems appropriate to distinguish two kinds of obliterating closure of vessels. In some cases, the cutaneous vessels are oblite-
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