Condition for work may be impaired or entirely destroyed in six ways. Disease, continued pain, idleness, excess of work, excess of food, and deficiency of food, all operate more or less against working condition. There are several other agents by which it may be impaired or destroyed, but those only which I mention seem to deserve particular notice.

Disease of a febrile character, or an inflammation in any of the vital organs, may attack the horse suddenly, and in one hour render him unfit for any work. If it were possible to remove such a disease on the same day, or at least in two or three days, the horse might still retain a portion of the condition he previously possessed. But this is not always possible. Between the disease and the cure the horse is much and unavoidably reduced. The debility which a febrile disease of itself produces, is often sufficient to destroy working condition as effectually as if the horse had never had any. Hence racers and hunters are often unfit to come to their work at the expected time. Perhaps influenza, or a similar malady, invades the stable, and for a time suspends all further training, and destroys that which has been given. It is the very same when the horse is at work. An attack of inflammation, or a fever in the middle of winter, throws the hunter out of the field for all the remainder of that season.

By or before the time he has recovered, and again been trained, hunting is over.

That which is true of the hunter or racer in this respect, is not less true of other horses. Their work may not require such a long and complicated course of preparation; but still they must have some. That which served at first may serve now, provided the disease be completely subdued. All diseases and fevers are not alike; while one may wholly destroy condition, another may only impair it.