The five varnished wooden boxes that Ray Kunze helped unload a few weeks ago from a van in front of the Uniformed Services University of the Health Sciences in Bethesda, Md., looked like they might hold croquet mallets.

But croquet mallets wouldn’t need the tiny holes that were drilled at the end of each box. Nor would croquet mallets make a creepily familiar rattling sound whenever they were bumped.

“You hear that?” said Kunze, a strapping Navy petty officer with a blond flattop as level as a billiard table. “They get out and start slithering, I’m running.”

The venomous snakes nestled inside the boxes — including two species of rattlesnake — were securely packed and padlocked, said Bruce Shwedick. The reptile expert had driven his fang-filled Ford Econoline van from Plant City, Fla., to present his annual “Snakes Alive” lecture to military doctors who may one day be glad they learned the difference between a Gaboon viper and a Malayan pit viper.

Shwedick, 44, makes the drive every year to be part of an annual tropical medicine course that’s taught at the nation’s university of military medicine. After muscling the boxes over a curb, onto an elevator, through the medical school’s hallways and into Lecture Hall D, Shwedick chalked a message onto the blackboard: “Welcome Don’t Panic.”

“That’s a good way to start the class,” observed Capt. Dominique Davenport, a family practice physician stationed at Fort Bragg, N.C.

While most of the peculiarly tropical ailments the students are learning about in the month-long course are caused by microscopic things — intestinal worms, protozoan parasites — this day was “critter day.” The 74 Army, Navy and Air Force physicians had earlier attended a lecture by an entomologist who talked about diseases spread by mosquitoes and ticks. A clinician briefed them on the toxic effects of certain tropical blowfish and the latest advances in treating snakebite.

Now it was time to see some of the venomous troublemakers doctors might encounter if deployed to the far corners of the globe.

“It’s one thing to read it in a book,” Davenport said. “It’s another to see someone who’s dealt with them in the environment.”

Snake eyes

The first snake Shwedick displayed wasn’t that dangerous — yet. It was a year-old anaconda named Jade. About four feet long now, the nonvenomous snake will eventually quadruple in size. Shwedick, dressed in explorer-ish khaki and boots, carried the snake through the amphitheater, showing it off to the children that some students had brought — and who Shwedick had insisted sit in the back row.

Florida snake expert Bruce Shwedick shows off a very poisonous Gaboon viper at his lecture for military medical personnel. Shwedick makes an annual appearance with his fanged friends at the Uniformed Services University of the Health Sciences, the nation's university of military medicine.

After putting the wriggling Jade back into a brown bag, Shwedick pulled a set of keys from his pocket and started unlocking the trunks.

First out was a copperhead, native to North America. Shwedick pointed out the hourglass pattern on the snake’s back, its reddish tongue and elliptical eyes.

“But you know what they say,” Shwedick said. “If you’re close enough to see a snake’s eyes, you might be too close.”

Next up: a cottonmouth, the bite of which, Shwedick said, produces “burning pain and a feeling like electric shock.” (He should know: He was bitten on the hand by one about 12 years ago.) It was followed by a timber rattlesnake, the rattles on its tail sounding like water dancing on a hot griddle.

From Central and South America came a lancehead, or fer-de-lance, a beige snake with a long head and highly potent venom that can cause “bleeding from gums and other body orifices.”

While the snakes up to this point had seemed either familiar or underwhelming, the snakes of Africa got everyone’s attention. Shwedick hoisted a Gaboon viper from its box. This is a snake of nightmares: beefy, patterned in shades of brown, with an angular, leaf-shaped head.

But it paled in comparison with the next treat. Before pulling out an African spitting cobra, Shwedick donned a pair of safety glasses and what looked like a riot policeman’s helmet. (A uniformed student seated toward the front discreetly slipped on her own tortoiseshell shades.)

In fine snake-charmer fashion, the cobra travels in a basket. When the lid was removed, the dark, glossy snake slithered out. Shwedick lifted it with a pair of hooked metal poles, moving them from front to back as the snake glided over them like a cascading length of black taffy, albeit taffy that can spray cornea-eating venom up to 12 feet into the eyes of predators.

Best to be prepared

If U.S. troops are sent to Liberia, they could come face to fang with such snakes, Shwedick said.

The military doctors also can be expected to see foreign civilians, who turn to them for treatment. Often, Shwedick said, a bite victim will emerge from the jungle, rainforest or sugar cane field with a machete in one hand and the head of the snake that bit him in the other. That’s bad news for the snake but useful for identifying the species and determining the appropriate antivenin.

But Shwedick urged caution: “A snake can still bite hours after its head has been severed,” he said.

Shwedick’s two-hour romp through the world of “medically important” snakes included appearances by a South American tropical rattlesnake, a horned desert viper (native to southwestern Iraq), a Malayan pit viper, a death adder (Australia’s deadliest snake) and an Asian cobra, which helpfully spread the ribs in its neck to create that distinctive hood shape.

“My favorite was the spitting cobra,” said Col. Bradley Harper, a pathologist from U.S. Army South in San Juan, Puerto Rico. “It can reach out and touch you.”