DISEASES OF THE SKIN. 



herpes, and they do not always form a scab as they subside, but termi- 

 nate in reabsorption of their contents, with desquamation. In herpes 

 iris a few solitary vesicles stand in the centre of a circle of vesicles, or 

 of several concentric circles of them, whose vesicles exhibit different 

 stages of development and decline. Most cases both of herpes circina- 

 tus and herpes iris, if not all of them, owe their origin to the presence 

 of vegetable parasites. 



TREATMENT. As the various forms of herpes run a cyclical course, 

 and as they soon subside, and are not followed by any serious conse- 

 quences, their treatment should be simply expectant. It is sufficient 

 to protect the vesicles, and the scabs after they have formed, from 

 friction or other violence. In herpes zoster, which is the most exposed 

 to friction, the eruption should be enveloped in cotton, which should 

 be allowed to remain just as in the treatment of slight burns. The 

 expectant treatment is especially advisable in herpes preputialis. The 

 spontaneous healing of an excoriation, which remains after the burst- 

 ing of a vesicle, affords the best confirmation of the diagnosis that we 

 have to deal with a herpes and not with a chancre. True, the diagnosis 

 is easy enough at first, as the grouping of the vesicles in herpes is 

 quite characteristic, and, in the excoriation which remains immediately 

 after they have burst, it is easy to perceive from its shape that it has 

 been formed by a cluster of several vesicles. Somewhat later, how- 

 ever (especially if the patient, in his anxiety, have cauterized them 

 with lunar-caustic), the diagnosis is more difficult, and frequently our 

 only sure criterion is in observation of their subsequent progress. If 

 the excoriation heal in a few days, under the application, twice a day, 

 of a bit of lint moistened in water, between the prepuce and glans, or 

 if the recovery is not delayed beyond a week, we may be sure that it 

 is not a chancre. 



CHAPTER VI. 



URTICARIA NETTLE-RASH ACUTE SUPERFICIAL DERMATfllS, WITH 



FORMATION OF WEALS. 



ETIOLOGY. In urticaria a serous infiltration of the papillae of the 

 skin, and, probably, too, a swelling and infiltration of the cells of the 

 rete Malpighii cause the formation of circumscribed flattened eleva- 

 tions, whose width is greater than their height, and which are called 

 weals. Owing to the rapidity with which the infiltration that pro- 

 duces the weals appears and disappears, we should not have reckoned 

 urticaria among the inflammatory affections, but should rather have 

 described it as a local oedema characterized by great peculiarities in its 



