I have mentioned all the different species of exercise, not because I think they all belong to the class of radical remedies for the consumption, but because it is often necessary to use those which are passive, before we recommend those of a mixed or active nature. That physician does not err more who advises a patient to take physic, without specifying its qualities and doses, than the physician does who advises a patient, in a consumption, to use exercise, without specifying its species and degrees. From the neglect of this direction, we often find consumptive patients injured instead of being relieved by exercises, which, if used with judgment, might have been attended with the happiest effects. I have before suggested that the stimulus of every medicine, which is intended to excite action in the system, should always be in an exact ratio to its excitability. The same rule should be applied to the stimulus of exercise. I have heard a well-attested case of a young lady, upon whose consumption the first salutary impression was made by rocking her in a cradle; and I know another case in which a young lady, in the lowest state of that debility which precedes an affection of the lungs, was prepared for the use of the mixed and active exercises, by being first moved gently backwards and forwards in a chariot without horses, for an hour every day. Swinging appears to act in the same gentle manner. In the case of a gardener, who was far advanced in a consumption, in the Pennsylvania hospital, I had the pleasure of observing its good effects, in an eminent degree. It so far restored him, as to enable him to complete his recovery by working at his former occupation. In cases of extreme debility, the following order should be recommended in the use of the different species of exercise. 1. Rocking in a cradle, or riding on an elastic board, commonly called a chamber-horse. 2. Swinging. 3. Sailing. 4. Riding in a carriage. 5. Riding on horseback. 6. Walking. 7. Running and dancing. In the use of each of those species of exercise great attention should be paid to the _degree_ or _force_ of action with which they are applied to the body. For example, in riding in a carriage, the exercise will be less in a four-wheel carriage than in a single horse chair, and less when the horses move in a walking, than a trotting gait. In riding on horseback, the exercise will be less or greater according as the horse walks, paces, canters, or trots, in passing over the ground.