PSORIASIS. 487 



palm of the hands and soles of the feet are reddened and covered with 

 dry scales. We have ascertained that this is really a species of eczema. 

 The circumscribed variety is always of syphilitic origin, and is to be 

 spoken of hereafter. The circumstance that the morbid process from 

 which psoriasis arises does not act continuously upon one spot for any 

 great length of time, is not only the reason for the peculiar figuration 

 of the eruption, but also accounts for the rarity with which degenera- 

 tion of the deeper layers of the skin occurs in this disease. The excep- 

 tional cases in which the eruption does not soon subside, and in which 

 the skin is thickened, rigid, and fissured, are called psoriasis inveterata. 

 The diffuse or irregularly extended variety of the disease is the one 

 most apt to assume this form. 



TREATMENT. Although it seldom is possible to effect a radical 

 cure of a psoriasis, yet the treatment which merely aims at a tem- 

 porary abatement of the eruption is very satisfactory. The objections 

 which exist against the local treatment of certain forms of eczema and 

 impetigo are not valid in case of the disease in question ; psoriasis is 

 never of constitutional origin, and never appears vicariously for other 

 diseases. Moreover, vigorous local treatment is tolerated much better 

 in psoriasis than in any other cutaneous affection hitherto described. 

 Psoriasis must always be treated locally and with the most energetic 

 remedies. Instead of the white-precipitate ointment, and the prepara- 

 tions of zinc and of lead, which often suffice to effect a cure of an 

 eczema or an impetigo, and which, indeed, are often the only remedies 

 applicable to the case, the articles best adapted to its treatment are 

 green soap, tar, and the preparations of sulphur. It is best to com- 

 mence the cure with one or two vapor-baths, in which, by means of 

 soap and a moderately hard brush, the skin is to be cleansed as much 

 as possible from the scales which adhere to it. If these vapor-baths 

 cannot be had, the same object may be obtained by means of long- 

 'continued warm- water baths. After removal of the scales, the green 

 soap is to be rubbed in twice daily, for a period of from three to six 

 days, or else it must be applied upon a compress, which is to be re- 

 newed twice in the day. While this is going on, it is best that the 

 patient should be enveloped in a woollen blanket, and that he should 

 remain in bed, and in a well-warmed chamber. The treatment should 

 then be suspended for about three days, during which the inunctions 

 should cease, and the compresses may be laid aside. At the end of the 

 interval, the patient must take another vapor-bath, or long-continued 

 warm-water bath. If the infiltration of the cutis has not yet disappeared, 

 the process is to be repeated. If, however, all the diseased spots seem 

 soft and pliant, we may proceed to the application of tar or of tar-oint- 

 ment (see page 476). We have already said that we prefer a solution 

 81 



