Having just now, with the help of the healing arts, recovered enough use of my right arm to grip a pen, I wield that pen to write this warning (to be pondered all winter) against the folly of summer vacations.

The phrase "family vacation" is, of course, an oxymoron. Children, with their unresting energy, overwhelm the adult pleasure from vacations -- the delicious feeling of truancy from everyday bustle. But for children, summer is supposed to be a souffle' of delights, both diverting and instructive. To that ambitious end I spared no expense of time and treasure.

I took the three Will siblings -- boys 18 and 16, and the Prodigy, 9 -- first on an Alaskan cruise, then to California. There, disaster, having bided its time, struck, to the delight of the children.

The cruise -- a Dutch ship magnificently crewed by Indonesians with exotic names like (really) Bambang -- suited father, who, lost in a deep deck chair and a shallow novel, knew the children would not leave the ship or, while on it, escape the captain's dread sovereignty. (I took the precaution of explaining to them, in hair-raising detail, the maritime punishment of keelhauling, and the eligibility of children for it.) The cruise was grand, but nothing lasts forever, alas, and a few days after docking I and the three were in Southern California, at the top of a water slide in one of those infernal amusement parks featuring water tortures that people inexplicably find fun.

Amusement parks refute the notion that ours is a species suited to self-government. What can be said in extenuation of people who pay to be whirled and flung about in ways that wrench joints and induce headaches and queasiness? Water parks are particularly Dantesque. There, you broil in long lines in the sun for the pleasure of plunging -- buffeted and sandpapered -- down a plastic chute into cold water.

When seating myself at the top of one such slide -- the Wipeout or Cobra or Nairobi Express, I forget which -- I tore something, or several somethings, in my upper arm. The next day that arm was useless, but the biceps had a pretty shade of indigo, with bright yellow trim. Soon I was in the fell clutches of modern medicine and fitted with a sling. Then I was subjected to the merciless merriment of the three ingrates to whom I improvidently helped give the gift of life.

Human beings differ in tastes. Some do and others do not like operas, popsicles, democracy, poetry. But there is one uniformity: All children adore seeing father brought low by injury. Not too low or for too long but sufficiently to be semi-incapacitated and awkward.

This allows them to poke the injured portion of him, inquiring with feigned innocence, "Daddy, does that hurt?" And they miss no opportunity to explain, loudly, to friends and even strangers, the silliness -- "It was on a water slide!" -- that got daddy the injury that they clearly think serves him right.

The pleasure children derive from a father's physical incapacity is political. Power is linked to authority, which is inextricably bound up with competence and dignity. An injury, particularly one that father suffers in ridiculous circumstances and that makes him fumble with doorknobs, subtracts from parent majesty and thus advances the emancipation of children.

Which is bad enough. Worse is the encounter with medicine and its intimation of mortality.

"Let me show you," says an orthopedist whose patients include Washington Redskins, heroic gladiators. He leads this victim of a parenting injury to a corner of his office and there patiently explains the shoulder mechanism by manipulating an alarmingly lifelike (deathlike, actually) skeleton. Just what I least want: another reminder of the skull beneath the skin of life.

There is nothing like a little bodily breakdown to make a middle-aged man feel the cold grip of withering age. "The bloom is gone, and with the bloom go I." Another doctor, preparing to pump air and dye into the shoulder joint (for a CAT scan), says something Torquemada probably said to victims of the Inquisition of the rack: "You are going to feel a certain tightness in the shoulder." This doctor says he is just a year younger than I, and last year he suffered a herniated disc. "We are just at the age," he says cheerfully, "when we begin to fall apart."

Where do doctors learn to says these things? Are there medical-school classes that teach banter calculated to supplant physical with mental suffering?

The prognosis is that if I am diligent at physical therapy, by the time next summer's vacation rolls around I should be, so to speak, ready to rip. Meanwhile, although the calendar says summer still has several weeks in which to inflict injuries, it is time to close the book on this season of suffering, while I still have one arm healthy enough to close a book.