Scientists identified antibodies that neutralized the poison in whole or in part from the bites of cobras, mambas and other deadly species.

The video is just under two and a half minutes long. A slim man with close-cropped hair walks into a room, pulls a long black mamba — whose venom can kill within an hour — from a crate and allows it to bite his left arm. Immediately after, he lets a taipan from Papua New Guinea bite his right arm. “Thanks for watching,” he calmly tells the camera, his left arm bleeding, and then exits.

Over nearly 18 years, the man, Tim Friede, 57, injected himself with carefully calibrated, escalating doses of venom to build his immunity to 16 deadly snake species. He also allowed the snakes — mostly one at a time, but sometimes two, as in the video — to sink their sharp fangs into him about 200 times.

This bit of daredevilry (one name for it) may now help to solve a dire global health problem. More than 600 species of venomous snakes roam the earth, biting as many as 2.7 million people, killing about 120,000 people and maiming 400,000 others — numbers thought to be vast underestimates.

In Mr. Friede’s blood, scientists say they have identified antibodies that are capable of neutralizing the venom of multiple snake species, a step toward creating a universal antivenom, they reported on Friday in the journal Cell.

“I’m really proud that I can do something in life for humanity, to make a difference for people that are 8,000 miles away, that I’m never going to meet, never going to talk to, never going to see, probably,” said Mr. Friede, who lives in Two Rivers, Wis., where venomous snakes are not much of a threat.