If Venice is on your vacation itinerary this summer, there may still be time to change your plans.

When my colleague Hobart Rowen checked out of his Venice hotel a few days ago, he took along one of its rate cards and brought it back to Washington for me. Bart had been staying at the Hotel Excelsior at the Lido, which was press headquarters for the journalists traveling with President Carter.

"I thought you'd like to see how much they charge for a room," Rowen said. "As you can see, the basic price of the room is 170,000 lira. To this, they add a 14 percent 'value-added tax' which comes to 23,800 lira, and then there's a 'sojourn tax' of 1,200 lira, bringing the grand total to 195,000 lira -- or $237.23 per night in American dollars. And that's just for the room. It doesn't even include a continental breakfast, which costs around $10."

At those rates, Bart, I don't think I'd have any appetite left. In fact, at $10 an hour just for a place to sleep, I think I'd be up all night worrying. REMINDER

A small suburban newspaper carried a story about Children's Hospital a few days ago, and several readers have asked me whether the story is true.

There may have been minor inaccuracies in the story but its basic thrust was correct: Children's Hospital had indeed taken legal steps to collect a bill that was five years old. Unfortunately, the story that appeared in print was incomplete and, as a result, misleading.

It might therefore be useful to review that the hospital's position with regard to payment for its services.

When a sick child is brought to Children's Hospital, the first concern of the staff there is to provide proper care and treatment for the child, whether or not its parents can pay some of the bill, all of the bill, or none of the bill.

No child is turned away because its parents can't pay.

However, in those cases in which parents are able to pay, or have insurance that will pay, every reasonable attempt is made to obtain reimbursement for the costs of treatment.

It would be irresponsible for the hospital to fail to bill its patients and make a businesslike effort to collect from those who can pay. The decision as to who can pay and who can't is not made arbitrarily. In this modern society, all of us have credit ratings, and creditors have access to a great amount of pertinent information about us. Whenever the office staff at Children's Hospital must make a decision about an uncollected account, it reviews such information and the family's financial situation with great care.

In the case under discussion, the hospital gave careful consideration to the family's ability to pay. Its conclusion was that the family had ample resources to pay its bill, particularly under an extended payment plan that had been worked out.

I did not ask about the facts upon which this conclusion had been based; in fact, I'm pretty sure that if I had asked, I would have been rebuffed. It would be out of character for Children's Hospital to discuss a family's financial status with outsiders.

In retrospect, the decision to press for payment appears to have been a resonable one, for on Friday the bill was paid in full, without any extended payments. There was no need to proceed with legal action.

What cases of this kind bring into focus is this: Each year, Children's Hospital must appeal to the community to contribute well in excess of $1 million to pay for care that was provided to children whose parents could not pay.

If the hospital failed to make a diligent effort to collect from those who can pay, it would have to conduct a major fund drive every month instead of once a year. THE DISMAL SCIENCE

In discussing the extent to which experts in every field disagree, I mentioned psychiatrists who testify for the defense vs. psychiatrists who testify for the prosecution. Eli W. Garfield of Salisbury asks:

"Don't you believe you would have been more on target if you had used government economists as your example?"

Yes, Eli. And I gave fleeting thought to writing it that way. But economists have been such a woebegone lot since stagflation descended upon us that I decided not to add to their miseries. THESE MODERN TIMES

What I was doing cannot truthfully be described as playing golf, so I'll put it this way: I was with three fellows who were playing golf at Indian Spring while I was getting as much exercise as the three of them combined.

One man, just back from a visit to Philadelphia, said, "When my daughter and her husband told me what they're paying to send their three children to camp this summer, I thought she was kidding. It didn't cost my parents that much to put me through law school."