1. The depression of the nervous system so characteristic of synochus and typhus, is much less in degree in scarlatina. Neither the physical nor the mental debility is as great. In the whole attitude and manner of the patient, as well as in his own sensations, there is less prostration. The disease is more nearly allied to a pure inflammatory affection than either of the preceding forms of fever. 2. Accordingly, the circulation is not only more rapid, but it is also more strong. It is not uncommon for the pulse to be 140 in a minute; in severe cases it is seldom below 120. Without being hard, it is more full and strong and less easily compressed than in the other forms of fever. 3. Corresponding with the activity and energy of the circulation is the increase of the temperature; the heat over the whole surface of the body is often intense and pungent. In this fever, the temperature, as indicated by the thermometer, rises several degrees higher than in any other. 4. The capillary vessels of the external skin, as is shewn by the bright and vivid colour of its characteristic eruption, are filled with blood. Often from the crown of the head to the sole of the foot, the external covering of the body is in a state of inflammation, and this inflammation constantly terminates in the death of the cuticle, whence it is thrown off by the process of desquamation. It is not improbable that the large quantity of blood which is thus spent upon the surface of the body, and which is thereby diverted from the internal organs, is one reason why the latter are not so much oppressed as in the other forms of fever. 5. Much as the external skin is loaded with blood, the capillary vessels of the internal skin appear to be equally turgid with it. This is indicated by the bright and vivid redness of the mucous membrane covering the mouth, the tongue, the fauces and the throat. That this redness extends beyond these external parts into the internal organs there is abundant evidence, because, although we cannot follow it with the eye, we can trace it by the signs of disordered function which arise.