“Why doesn’t the United States have bidets?” a friend of mine visiting from Argentina asked recently.

I didn’t know the answer. Xenophobia, probably. Just because the French, the Argentines and half the rest of the world install a second bowl beside the toilet bowl doesn’t mean Americans are willing to go that route. We’ve always been suspicious of foreign entanglements.

Beside, when our nation was founded, this continent was blanketed in great swaths of virgin forest. Settlers looked at all those trees and said: “Those would be perfect for turning into rolls of paper that are both strong and soft.”

This is all a long way of returning to a topic I wrote about a few weeks ago: toilet paper — specifically the way the rolls have swollen to such proportions that they’re hard to fit in the TP holders of older homes. Many readers chimed in with their own gripes.

Nancye Vermillion, an Alexandrian living at the beach in Delaware, pointed out that the cardboard core of most toilet paper rolls is growing in diameter, “adding to the illusion that the supply on the roll is greater, when in fact, only the empty space in the center of the roll is.

“I have noticed this only because I’m the only one in my house who knows how to change the roll when it’s empty.”

Got that, Vermillions?

Sue Pierce noticed the cardboard getting bigger about five years ago, when her daughter-in-law was making craft projects from toilet paper rolls.

“At the time we had a small second home and spent a few months there each winter,” Sue wrote. “I started tossing the tubes into an empty drawer in the bathroom there to save for her.”

When Sue compared the new with the old, the difference was striking. I imagine it was like a paleontologist tracking the evolution of a mammalian species through changes in its fossilized teeth.

Speaking of those tubes, Alexandria’s Carole Appel told me something I didn’t know: Every cardboard cylinder has a serial number inside.

“How did I find out such an arcane fact?” she wrote. “Well, a few years ago, when I went to lift off the top layer of paper from a roll of Charmin toilet paper — that layer that’s attached to the sheet underneath by a few pressure points — layers wouldn’t separate in the usual way. Instead, the top sheet ripped through the next sheet, and through the sheet under that.”

The whole roll was glued together, from first sheet to last — so were the other 11 rolls from the batch Carole had purchased. She called Charmin to complain and was told to check the serial number inside the roll.

“So I tore open the last gray cardboard cylinder I’d tossed into the wastebasket, and sure enough there was a number,” Carole wrote. Carole provided the number, and Charmin sent her a coupon for a dozen free rolls.

Rolls may be getting fatter but sheets are getting narrower.

“If you compare the width of a currently manufactured roll of toilet paper to the width of that built-into-the-wall toilet paper holder, the difference is dramatic,” wrote Nancy Hoadley of Falls Church. “If the present rate of shrinkage continues, soon we will be using a ribbon of toilet paper to wipe our derrieres. Not a good scenario.”

Some readers have made their peace with the big rolls. Rose Mary Padberg lives in an older house in Arlington. “My suggestion for fitting the large roll into the ceramic TP wall holder is to keep it on the floor until it is used up enough to fit into the holder,” she wrote. “However, I do not like the look of the roll on the floor.”

Claudia Kilmer has a similar issue in her 66-year old house in Old Town Manassas. “When I notice the installed TP roll getting low, I put a brand-new roll (from Costco) on the floor next to the toilet,” she wrote. “We judiciously pull from both rolls, so by the time the old one is ready to come out of the holder, the new one has been reduced to fit. Not particularly ingenious, and it works.”

Marc McGee prefers the large rolls because of their capacity, but he too lives in an older house with small holders. Wrote Marc: “To avoid having visitors use fresh rolls sitting on the tank top or sink, I keep a supply of ‘guest rolls’ which are used down about a third so I can fit them in before anyone arrives.”

Some people try to cut down on TP usage considerably. Several female readers recommended a reusable square of antimicrobial fabric called a Kula Cloth — strictly for No. 1. The manufacturer claims “It will completely uplevel your adventure game and you will feel clean and dry and never disgusting.”

It’s aimed at hikers and campers but some people use them in their homes to spare the trees.

But toilet paper isn’t the only paper product to have changed over the years. A reader named Rick from Falls Church is a fan of Bounty paper towels.

“Now their ‘HUGE/ENORMOUS’ rolls do not fit my (expensive and kitchen-matching) wall mounted holder,” he wrote. “I have to search stores for the more ‘regular’ size rolls, which are getting more difficult to find. And looking at the small print about the size/number of sheets requires a math degree (which I have) to determine the roll size.”

What’s the paper towel equivalent of a bidet? One of those hot air hand dryers?

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/john-kelly.