adult, but that in infancy or childhood it is powerless to prevent a relapse. Cases have come under my care in which, within a short time after apparent recovery, the disease has returned in its original state; and I have known other examples in which arsenic has been persevered in, but only kept the complaint in check.

CHAPTER X.

General characters.

Varieties.

PORRIGO.

THE custom, heretofore, of arranging under a single denomination, diseases which are essentially distinct, is perhaps nowhere more apparent than in the so-called varieties of Porrigo. In proof of this, I have only to mention the "six specific forms" according to Willan, of the complaint, which heads the present chapter. The ill effects of this nomenclature are, in many instances, perpetuated to this day; and the expressions Porrigo favosa (favus), and Porrigo decalvans (alopecia), suggest or at least imply, the idea of affections which possess something more in common than a prefix to their name; and yet none can be more unlike in their history, course, and termination.

In describing porrigo, I purpose to limit its signification to one disease, and accept the definition of it as proposed by Mr. Startin, viz. that it consists of an eruption of large flat pustules, covered with thick crusts, and is contagious; it occurs on an otherwise sound skin, without a surrounding inflammatory base.

The division of porrigo into P. simplex, P. larvalis, and P. scutulata, is an arbitrary arrangement, arising from certain peculiarities in form which the disease presents. Thus it is styled Porrigo larvalis, when by the union of the crusts on the face, it bears a kind of resemblance to a mask. The eruption in this case

generally involves the cheeks and part of the nose in a single mass; or the same character may be equally assumed, when the forehead and eyebrows are simultaneously attacked. Porrigo scutulata is merely a term of the same complaint, in any case distinguished by the crusts being large and shield-shaped; they are often, as it were, stuck on to the surface. In Porrigo simplex the disease is seen in its mildest stage.

In

the disease.

The earliest sign of porrigo is shown by an eruption Course of of small flat pustules, not much raised, and containing, at first, a thin yellowish fluid, which soon concretes ; and to the successive secretions in the pustule, the resulting scab owes its size and prominence. When situated on the scalp, the pustules are usually distinct, the intervening portion of skin being quite healthy. this region they mostly select the occiput; they rarely commence on any other portion, although the lateral and frontal parts of the scalp may become successively attacked. The disease is easily recognised in many cases by simply placing the hand over the affected surface, when the characteristic elevations are at once detected. An enlargement of the cervical glands is another symptom which commonly attracts the notice of the patient: they may be felt as a chain along the inner border of the sterno-mastoid muscle; after attaining a certain size, they generally remain quiescent for months, and finally disappear. Frequently we find, coincident with the disease in the above locality, one or more of the fingers presenting at their extremities, or near the knuckles, painful boils or whitlows. Next in frequency to its occurrence on the scalp, and sometimes coexistent with it, a similar disease is discovered on the lips, chin, cheeks, or forehead; or any one of these localities may be

Microscopical charac

ters of the

hair.

alone involved. In other cases the loins are the seat of porrigo, just above the buttocks, and in this situation the pustules are mostly separate. As the crusts dry, fragments of them become detached, and loose masses are often found scattered among the hair, should the scalp be affected. They are not however of the thin, yellow, or scaly character which so distinguishes eczema in its final stage. Although they are renewed, if the scales fall off at an early period, or become otherwise detached, the subjacent skin is only thin and reddened; seldom is it ulcerated. The patient complains of irritation and itching of the part, but this is not severe; nor is there, except in extreme cases, any signs of constitutional disturbance.

Although I have been unable to discover a parasite

JJJ

1.

(vegetable) in porrigo, the hair presents, in a vast number of cases, the following curious condition, which is not seen, as far as I know, in any other affection :the bulb becomes flattened, and expands into a broad and thin plane, which terminates in an even edge. In the figs. 2, 3, and 4, the expansion of the hair bulb is very evident. Fig. 1 is club-shaped at the root, but this character is witnessed in other cutaneous complaints. The lower part of each hair, extending to the bulb, exhibits a series of irregular rings; but this again, is not peculiar to porrigo, although well exemplified in this disease.

tween the

Porrigo is a complaint most common in childhood or Ratio bein infancy. It attacks both sexes in a nearly equal sexes. degree. Of 400 cases, in Mr. Startin's practice at the Skin Hospital, which occurred between the middle of June, 1860, and the end of January, 1863, I found 204 were females and 196 males; a difference of only 19:20 between the two sexes. In this estimate no account is taken of another and considerable class, in which the disease has spread to the other members of the family. I have recorded those cases only which have presented themselves at the hospital, and were under my own observation there.

Occurrence.

The various periods of life, at which the development Age of its of porrigo took place, is exhibited in the annexed table. Of 400 cases

292 occurred at and under the age of 7 years.

46 between 7 and 14 years of age.

The greatest age at which it occurred was that in a

man aged 55 years. The remainder were all below