In the course of two or three days from their first appearance the little pimples, increasing in size, will be found to contain a thin transparent fluid, to pit or become depressed in their centre, and the skin in the spaces between them will be found red.  On the seventh or eighth day from the commencement of the fever, the fluid contained in the pimples will be no longer transparent, but opaque; and they will consequently appear white, or of a light straw colour.  Each pimple or pock will be no longer depressed in its centre, but will become raised and pointed, being more fully distended by the increased quantity of fluid within; and the skin around each pock will now be of a bright crimson.  The head, face, hands, and wherever else the eruption shows itself, gradually swell; and the eyelids are often so much distended as to close the eyes and produce temporary blindness.  There will always at this time be some degree of fever present, and its amount will vary with the circumstances of each individual ease.  The skin too will be very tender, so much so sometimes as greatly to harass and distress the child.

On the eleventh day the swelling and inflam of the skin of the body and face subside; the pimples upon these parts dry up and form scabs, which fall off about the fourteenth or fifteenth day.  Those on the hands, as they come out later, commonly continue a short time longer.  The eruption leaves behind, in some cases, the peculiar marks of the disease; and in others merely discoloured spots, which disappear in the progress of a short time.

The natural small-pox is sometimes much more severe in its character than the foregoing, and what is called confluent small-pox is said to exist.  This form will be marked by great constitutional disturbance, and the eruption coming out earlier than in the milder form; instead of being distinct, that is, each pimple standing distinct and separate one from the other, they will coalesce, and appear flat and doughy, not prominent:  they will more particularly run into each other on the face, where they will form one continuous bag, which soon becoming a sore, will discharge copiously.

Small-pox in the vaccinated.—­When small-pox occurs to those that have been formerly vaccinated, the disease, in almost every instance, is much altered or modified in its character.  Indeed in children, in whom of course vaccination has been but comparatively lately performed, small-pox when it occurs will, in the majority of cases, be so mild that the real nature of the disease will be with difficulty determined:  so mild, that again and again has a parent been heard to exclaim, “Surely these few scattered pimples cannot be the small-pox!” If, however, as the pimples progress, they are narrowly watched, and are seen to become depressed in their centre; if there has been the precursory rigor, etc.; and if the source of the disorder can be traced to some case of undoubted small-pox, the child in fact having been exposed to contagion, no doubt ought to exist in reference to the nature of such a case, however slight may be the character of the disease.