Spit: What’s Cool About Drool

This drool-worthy nonfiction book rigorously defends the intriguing thesis that spit “is actually the unsung hero of our time – or at least of our mouths.” Early chapters outline the important jobs spit (“or slobber, drool, saliva or whatever you like to call it”) perform in the human body, from helping to speak to aiding in digestion. The healing and life-saving properties of spit are explained in the “Spit for Your Health” section that delves into saliva screenings used for hepatitis C and HIV detection. Other chapters explore creatures, like snakes, llamas, and the slow loris (the only venomous primate), who wield their spit like a deadly weapon.

The considerable amount of scientific information is presented in a playful, conversational style: ““Ew, all this nasty stuff in my mouth?” you might ask. Don’t panic.” Terms like bacteria, enzymes, microbiome, and DNA are highlighted in the sidebars by marquee-like signs with the headline, “INTRODUCING …” Other pages profile spit experts like van Leeuwenhoek, “the father of microbiology”, who made microscopes in the late 1600s; physiologist Ivan Pavlov; and Dr. Robert Koch, the German doctor who discovered the cause of tuberculosis. Trivia fans will savour all the quirky facts provided, like, “Each year the average person produces enough saliva to fill two bathtubs.” Puns abound, making for lots of entertaining and enlightening read-aloud opportunities.

Cultural and historical attitudes towards spitting are also examined. If you violate the no-spitting law in Singapore, it can cost up to $733 for a first offense. In the late 1880s, New York City issued a booklet of health recommendations for citizens that advised against “persons suspected to have consumption to spit on the floor or on cloths unless the latter be immediately burned.” Readers may also be gobsmacked at the superstitions that are still practiced, like baseball players spitting into their hands before going up to bat to bring them good luck.

Funny cartoon illustrations by James Braithwaite reinforce concepts explained in the text and are reminiscent of Gary Larson’s Far Side comics. In “One Small Slurp for Mankind”, a frog sticks out his long slobbery tongue and catches a stunned astronaut in a space shuttle, with the caption: “Although he knew a frog tongue is faster than a rocket launch, Buzz was still unprepared for this ride.”

Veteran science writer Mary Batten includes the right dose of gross. The final chapter of Spit: What’s Cool about Drool looks at competitive spitting contests, like the one held annually at Purdue University in Indiana. The Bug Bowl has this oddly heartening rule: “If you accidently swallow your cricket, you get one more chance before being disqualified.”

There is lots to chew on in this informative and engaging book.