CONTAGIOUS IMPETIGO.
The affection known as contagious impetigo, though a very common one, is by no means as clearly defined as other dermatoses of frequent occurrence. Crusted lesions or scabs resulting from the use of the finger nails and the drying of a copious blood-stained secretion are frequently seen upon the faces of children, but the origin and nature of this eruption are hot always plain. That the lesions are contagious and auto-inoculable is a matter of simple observation, and that pus cocci play an important part in their development is generally admitted. Mothers and nurses are often affected by children under their care.
It is undoubtedly the presence of micro-organisms which occasions the crusted or impetiginous form of eczema (the crusta lactea, or milk crust of infants). In these cases we have an ordinary eczematous inflammation of the skin due to some internal condition, but the peculiar clinical aspect of the eruption—viz., the suppuration and crusting—is without doubt due to the external agency of pyogenic microbes. In other cases minute aggregated pustules develop superficially and exude an abundant honey-like secretion which dries into yellow, gummy crusts of varying size and irregular outline. This eruption is comparatively rare, affects adults as well as children, and is by some regarded as a pustular eczema and by others as impetigo or contagious impetigo. In fact it is difficult to determine in practice precisely what cases should be included under the last-named affection, but a large number of cases occurring in children present certain definite lesions which are readily recognized and indicate an identity of origin.
In a typical case of contagious impetigo (and it is questionable whether there is any impetigo which is not contagious) the lesion is usually a flattened vesico-pustule. This is small at the outset, superficial, and without any surrounding area of inflammation. It is always single, although when the pustules
