(From to springforth like a flower). Rash. Effloratio, efflorescentia, and epan-thesma. Red patches on the skin, variously figured, in general confluent, or diffused irregularly over the body, leaving interstices of a natural colour. Portions of the cuticle are often elevated in a rash; but the elevations are not acuminated. The eruption is usually accompanied with a general disorder of the constitution, and terminates in a few days. Fevers attended with these appearances are called exanthematous.

Exanthemata form the third order of Dr. Cullen's first class, pyrexiae; and the propriety of establishing such an association will be obvious on the slightest consideration. It is so truly natural, that the doubt will only be whether it is not more properly a genus. The limits, however, of such an order are not easily fixed. If we look at some of the genera, the small pox and measles for instance, the limits will appear to be cutaneous eruptions from a specific virus, which produce the disease once only in the individual's life. This future immunity, however, is not constant to all the genera; and it is found in diseases not included in the order. Thus erysipelas, probably urticaria, more certainly pestis, recur in the same individual, while pertussis only attacks once in the life. We might refer to what we have said on cutaneous diseases, and endeavour to establish, on the same foundation, all the affections of the ephelion, but that the epidemic catarrh would stand in the way of the conclusion.

In the definition therefore of the exanthemata, the circumstance of the diseases affecting the person only once in their lives must be abandoned, or the erysipelas, and probably some others, must be expunged. In other respects the order is perfectly natural, if we exclude the plague, which, as we shall hereafter point out, connects the exanthemata with the fevers; and such connections as, in the natural method of botany, will be probably found important. In other respects the theory of the exanthemata has been already explained under the Cutanei morbi, and require no further elucidation than they will receive under the article Febris, q. v.