Never toss a hat on a bed. Always close a holy book when you finish reading it. Spit three times when you hear good or bad news.

Many of us grew up hearing and adhering to these and other Jewish superstitions. Often they defy logic. But, like chicken soup to fend off a cold, we follow the sometimes-arcane directions because, hey, it couldn’t hurt.

Barbara Hoffman remembers her mother’s caution: “Don’t cross your legs, because if you do, you’ll marry a tailor.” She followed the advice and married a doctor.

Eat fish on Shabbat evening and Rosh Hashanah, said Carol Rose, because “a fish’s eyes go up, and you should position yourself with your eyes heavenward. Also, fish were the only living things that survived the flood.”

“You’ve got to have good stars,” advised Gloria Morgenstern. “They must be lined up just right. And say ‘Kenahora’ — (from Yiddish and Hebrew keyn ayin hara) which means ‘stop the evil eye!’ ”

“What about bringing salt or jam to someone moving into a new home,” offered Malcolm Barnett. “Or touching the mezuzah on the doorpost when you enter.”

Both are intended as a protection of sorts, but there is a clear distinction between salt or jam (a superstition) and the mezuzah. This is where traditions sometimes get hazy. It’s important to remember we follow some practices because they are so written in the Torah, according to Rabbi Yosef Landa, director of the St. Louis Chabad.

“Having a mezuzah on the door is a commandment (No. 21), one of the 613 commandments of the Jewish faith,” Landa said. “It also has protective qualities and protects whoever goes into the house, keeps out what is not good.

“The fact that the mezuzah has protective qualities is part of the holy books, part of the religion. It’s not going to physically keep a burglar out, but it has spiritual powers because it is a divine commandment that brings with it blessing and protection.”

Keeping evil spirits out of the house requires a bit more cunning, and perhaps a trip to Schnucks, says Howard Schwartz, Jewish scholar, author and professor emeritus of English at the University of Missouri-St. Louis.

“To ward off the demons and neutralize the evil spirits, you give them something to eat – and what they like is jam,” Schwartz said. “The story I remember, one of those oral stories, is there’s a wedding of demons, and they leave them jam so the demons won’t be destructive.”

Landa offers another, less macabre reason for bringing jam into a new home.

“It’s a sign of blessing, a sign of sweetness,” he said. “You want the new home to be filled with blessings, and jam is as practical and pragmatic as you can get. It’s something that you can sink your teeth into, so to speak.”

Tradition, tradition

Some long-held superstitions are truly bubbe meises (old wives’s tales), Landa said, because the notion of free wielding evil spirits is inconsistent with Jewish beliefs. But a number of St. Louisans I spoke with recalled the practice of using salt to keep bad vibes at bay.

The superstition suggests you put salt in the corners of an empty room, or in the pockets of new clothing. Goblins and elves look for crevices to hang out in, but salt makes those hideouts less inviting. Pepper is an alternative, but if you inhale it and sneeze while you’re talking, that’s a sign you are speaking the truth.

Some superstitions are part of Jewish culture, which is why we keep them alive and pass them on to future generations, Landa said.

“We have a long and detailed recorded tradition,” he said. “There are some mystical practices and there are some bubbe meises, but they’re hallowed by tradition, and because we are a people of tradition, we hold on to them because there’s a nostalgia to them.”

Landa said a little research might reveal the origin of some superstitions.

I tried to figure out why throwing a hat on a bed is considered bad luck. Folklore tells us it’s those pesky evil spirits. However, the rationale could be in physics (a shock from static electricity released when removing a hat from your head and tossing it) or hygiene (preventing an infestation of parasites).

It’s also unwise to put shoes on a bed, at least according to playwright Neil Simon. You may recall in “Brighton Beach Memoirs,” when Kate Jerome scolds her son Eugene Morris Jerome: “Hey – shoes on a bed! Bad luck in a Jewish house!”

Another superstition that comes up often is the practice of spitting three times – “Pooh! Pooh! Pooh!” – after hearing bad news, or even good news.

The reason: If it’s bad news, you spit three times to ward off the evil eye so that the same thing doesn’t happen to you. You also do it when you hear about something good so that the evil eye doesn’t come and spoil things.

One tradition with some superstitious overtones is the breaking of a goblet or glass to end a Jewish wedding ceremony. The generally accepted reason for breaking the glass is to commemorate the destruction of the temple in Jerusalem 2,000 years ago. The destruction of the glass is a reminder that there is destruction even in moments of happiness.

Joshua Trachtenberg writes in “Jewish Magic and Superstition” that the custom may have originated to ward off evil spirits, and specifically a particularly nasty spirit named Lilith. She was quite the troublemaker, associated with disease, illness and death. Howard Schwartz learned a particularly ghoulish tale from his father: When a man dies, all the demon offspring he has fathered with Lilith (who is the incarnation of lust) will gather around him, crying out his name.

Madonna, Ariana Grande and Mariah Carey are a few celebrities known to wear red wool thread on their left wrist as an amulet to ward off evil spirits. It also has been known to increase fertility and protect a soldier from injury. None of the three singers is Jewish, but they all study Kabbalah. You can easily make an amulet out of red yarn, or obtain an “OFFICIAL Kabbalah Red String Evil Eye Protection Bracelet” from Amazon.com for $27.95.

Another superstition also involves thread. If you are wearing clothing while someone is sewing a button or mending a tear, put a piece of string in your mouth to guard against misfortune.

Protecting against evil and other pesky spirits

Schwartz explained why so many superstitions are related to keeping evil spirits at bay. It’s because demons and spirits date back centuries.

“By the Middle Ages, it was believed that you had 10,000 demons on your right hand and 100,000 demons on your left hand,” he said. “You’re constantly in a battle with demons. And the Hamsa is a Middle Eastern symbol, an eye in the hand, and the eye is supposed to ward off the evil spirit.”

Hence, many superstitions are intended to confuse, mollify or offer up treats (like a jar of Smucker’s strawberry jam) to the evil spirits. All spirits need to be handled carefully. That’s one of the reasons we cover mirrors in a house of Shiva.

“Covering the mirrors is a Jewish tradition,” Schwartz said. “And if you ask 100 rabbis, you’ll get 100 different answers. Traditionally, the real reason is the mirror image of the person who has died is trapped in the mirror and you must cover it over or the spirit will cause damage or harm you.”

Another common custom after coming home from a funeral: Wash your hands, or you’ll bring death into the house.

Years ago, Schwartz learned of another unusual practice from the late Gershom Scholem, who was considered the preeminent modern scholar of Jewish mysticism.

“When a person dies in some Orthodox communities in Israel, they do not take a direct path to the cemetery,” Schwartz said. “They travel in a path that goes all over in order to lose the demons on the way there. The object is to avoid alerting demonic offspring who will try to steal your inheritance.”

Remembering the myriad Jewish superstitions can make a person’s head spin.

• Wear a metal pin on clothes when embarking on a trip. Metal is the product of advanced civilization, so it protects against less sophisticated evil spirits.

• It’s good luck if it rains or snows on your wedding day.

• A new bride who cracks an egg and finds a double yolk should eat it to make sure she’s blessed with many children.

• Place a prayer book under the mattress of an infant to keep the child from harm.

And speaking of books, there’s the superstition that you should always close a book (especially a prayer book) when you’re finished reading it. Again, this is to guard against the pesky evil spirits who might steal holy knowledge and use it for evil purposes if the book is left open.

Another Jewish superstition suggests you shouldn’t boast about your good health or great wealth lest you be stricken with an illness or see your investments take a nosedive. Rabbi Landa suggests this may be rooted in the Talmud, which states, “A man is judged every day.” Bragging about your good fortune demonstrates a lack of gratitude, he said. On the Day of Atonement, that could backfire, and the next year might not be as positive.

You’ve heard the old stage expression “Break a leg!” that actors call out to each other, ensuring a solid performance. One of the many possible origins includes the Jewish superstition in which you say the opposite of what you mean to confuse the evil eye. If you hear someone say to a mother, “Your child is really ugly!” it may be to protect the child from harm. It might be unwise if the mother isn’t familiar with the custom.

Similarly, a person who is quite ill can have his or her name legally changed, again as misdirection to fool the angel of death. Harry Cornbleet said this trick was used with his grandfather.

“My dad told me his father was originally named Yitchak (Isaac) in Russia,” Cornbleet said. “But when he became very ill as a child, his parents changed his name to Chaim Yitzhak, because Chaim means life. When he came to America, he changed his name to Hyman.”

Does it really make any sense to adhere to these age-old Jewish superstitions?

Tsila Schwartz, a local Judaica artist and calligrapher (and the wife of Howard Schwartz), suggested it is part of our culture.

“I grew up in Israel, and they have all kinds of superstitions,” she said. “If you don’t subscribe to superstitions there, people think something is wrong with you.”

A scientist would likely scoff at them, but why not follow tradition — just to play it safe. Even the Sefer Hasidim (“The Book of the Pious”) offers this sage advice:

“One should not believe in superstitions, but it is best to be heedful of them.”