Sister Mary Brigh Cassidy, who was administrator of Saint Marys Hospital from 1949 to 1971, and who died in 1992, said in a letter long ago that Saint Marys dropped the apostrophe in its name sometime after 1940, as a branding matter.

Today's column is all about mystery.

Over the many years I've penned this column for readers worldwide, one of the most common queries and haunting mysteries is, why doesn't Mayo Clinic use an apostrophe in "Saint Marys Hospital"?

No one seems to have a good, clear answer about how and why that apostrophe was discontinued, contrary to timeless rules of punctuation. I've simply attributed it to a modernization craze from 50 years ago or thereabouts.

But Ken Allsen, an Answer Maniac and local historian, thinks he may have found the smoking gun. "I was doing a bit of research today, reading the detailed history prepared for the 100th anniversary of our local Franciscan Community in 1977. I stumbled over a footnote reference to a letter written in 1955 by Sister Mary Brigh Cassidy, then head of Saint Marys Hospital.

"Obviously replying to an inquiry about the ungrammatical missing apostrophe, she states, 'After 1940, Saint Mary's Hospital deleted the apostrophe. The present title, which functions as a trademark, is Saint Marys Hospital.'

"I thought of you when I saw this and decided to share it with you in case the questions ever arises again. I think Sister Mary Brigh is an unimpeachable source on this one."

Yes, if Sister Mary Brigh, who led Saint Marys for 22 years and died in 1992, was the source, you can probably take it to the bank. FYI, Sister Domitilla DuRocher was the administrator from 1939 to 1949.

One mystery solved. Here's the next one.

A while back, I reminded you that the backwaters of the Mississippi River in the Wabasha area tend to smell like my kitty's litter box in springtime, and to some degree through the summer, and that experts really haven't explained it.

It's an annual puzzle to be solved, and an excuse for me to have some admittedly juvenile fun with puns involving words such as "urine."

Not long after that memorable column on May 16, a reader named Hunkey D. yearned to have his theory on the record:

"I'm surprised you could not figure this out -- being from a river town, we all know it is the start of the mayfly season. In the stagnant waters, the larvae come to the top of the water and pugh..."

Hunkey thinks he's flushed out the truth, but frankly, the mayfly angle is too easy and doesn't really explain the summer-long odor near Nelson, Wis., as opposed to up and down the river when the mayflies are ripe. But I'll grade that theory P for plausible.

Keep trying. We'll get to the bottom of this yet.

And the final mystery of the day: I'll have more evidence on Tuesday regarding the Mystery of the Disappearing Statues. Two amateur sleuths have turned up details about the missing Lincoln and Washington statues that were gifts to the city from the Mayo family more than a hundred years ago.

Get your shovels ready.

The Answer Man is THE unimpeachable source. Send questions to P.O. Box 6118, Rochester, MN 55904 or Follow him on Twitter, @PBanswerman.

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