The body operates with a finite vital force and interrelated organs that require careful preservation to maintain health.

Original passage

God has endowed us with a certain amount of vital force. He has also formed us with organs suited to maintain the various functions of life, and He designs that these organs shall work together in harmony. If we carefully preserve the life force, and keep the delicate mechanism of the body in order, the result is health; but if the vital force is too rapidly exhausted, the nervous system borrows power for present use from its resources of strength, and when one organ is injured, all are affected. Nature bears much abuse without apparent resistance; she then arouses and makes a determined effort to remove the effects of the ill-treatment she has suffered. Her effort to correct these conditions is often manifest in fever and various other forms of sickness.