Campitis -- probably the most prevalent of childhood diseases -- strikes with virulence in summer, and it seems to strike the child of the working mother worst of all.

Suddenly your child swears total sickness as he covers his mouth with his hands, blows out his cheeks, gags and runs to the bathroom when the bus arrives for tennis camp, swimming camp or camp camp.

You have several options: 1. You can persuade yourself that your child is really sick and rush to the doctor for an emergency visit where you will be put in the Sick Children's Corner so you can both be sick next week; or 2. You can say, "Nonsense," and boot your child, sniveling, out the door and then feel guilty all day; or 3. You can let him stay home with a sitter, but in bed with no company, no television and a diet of thin gruel; or 4. You can mutter, "What will it matter in a hundred years?" and give the day over to your child.

Personally, we usually choose No. 4. An occasional summer holiday will soothe your soul and give your child what he needs most: you

Campitis, after all, is a child's way of telling you (and maybe even himself) that his schedule is a little more than he can handle right now.

This may mean taking our child to work with you, treating him as adultly as you can and going out to lunch together; but it's generally better if he can putz around the house with you, taking it quiet and easy with few chores, no pressure and little television or record-playing -- all techniques to help a child feel free enough to talk about the problems that niggle at his mind.

This is also the day your child can learn a lot of things that aren't part of day care. A day to Fool Around: to take your child marketing -- not to the Safeway, but to Savage's, the Seventh Day Adventist store in Takoma Park that sells such beautiful produce, and pork chops made of nuts; to the German Deli at 814 11th Street NW, where English is the second language, sausages are superb and foil-wrapped chocolates come in a hundred shapes. It's even a day to take that hour-long drive to Lexington Market in Baltimore. Here horseradish and coconut are grated fresh and ethnicity is so strong it could be packaged by the pound.

Each of these small adventures is really a series of culture shocks that subtly tell a child, "Hey, there are a lot of different folks in this world." It's education like this that helps a child empathize with others around him -- even parents.

Fooling Around is the time when you sit down together to fix the photograph album, settling in with five years of snapshots to mark, one by one.You remember the time you went to Great Falls for the seventh birthday party, and when you had that breakfast picnic on the Mall. There is the picture of Cousin Sadie, long forgotten, and Uncle Tom, who never could be, and all the strange and funny stores about them that your child has never heard. Although the album barely gets started, the time is not idled away: When a child knows who he is and where he fits, he fills one of the most primitive needs he ever will have: he finds his place.

If memory lane is not the sort of Fooling Around you care bout, you can turn to the garden -- by bringing it indoors.

Have your child start with a lettuce garden by putting halves of empty eggshells back into their carton, with a hole through the bottom of each shell for drainage. Fill them with vermiculite, poke a couple of lettuce seeds in each of them and add some water. Water daily until they sprout, then put the carton in the sunlight, to transplant when there are at least four leaves on each plant -- since the first two are not leaves at all, but merely the division of the seed itself.

And then there's this business with ligustrum -- an amusing and even a rather scientific thing to do, for it teaches a child how plants get fed.

Buy some glycerin at the drugstore and then prune ligustrum or any tree or shrub in the yard, as long as the leaves are pretty (so you will like the results) and green (so you know the sap is running).

Have your child hammer two inches at the end of each stem. In a bucket mix one cup of glycerin and three cups of hot water. Plunge the stems in the bucket for one to three days. That's it. Like magic, the hot water carries the glycerin up the veins to the very top leaves, as if it were sap. Your child will see the leaves turn slightly oily to the touch and change color as it travels. Magnolia becomes bronze; dogwood a bright green and ligustrum turns into a rich, rich brown. This dried foliage keeps for years, without water and with a fine, sophisticated style.

And if none of this appeals to you this time -- that's all right. Parents can get campitis too -- and that's when you send your child out the door, sniveling -- and without feeling one bit guilty about it.