The natural instinct to defecate, like many other natural instincts, is

usually deadened by failure to exercise it
The natural instinct to defecate, like many other natural instincts, is
usually deadened by failure to exercise it. Civilized life makes it
inconvenient to follow this instinct as promptly as, for instance, a
horse does. The impulse to go to stool, if neglected even five minutes,
may disappear. There are few health measures more simple and effective
than restoring the normal sensitiveness of this important impulse. It
may require a few weeks of special care, during which cold water enemas
at night, following evacuation by paraffin oil injection, may be needed.
It would be an excellent rule to visit the closet immediately after the
noon and evening meals, as faithfully as most people do after the
morning meal, until the reflex is trained to act at those, the most
natural, times for its action.