The trip late last summer was particularly adventurous. It would last six weeks, taking Slowinski's team 200 miles into the barely inhabited north of Myanmar, near the border of China, high into the foothills of the Himalayas. The expedition started off on foot. Slowinski had taken along bird and frog experts; he took along a photographer from the California Academy of Sciences, in San Francisco, where Slowinski was himself a curator. He also brought along the young Burmese scientists he was training -- he was teaching them how to inventory their own forests' biological diversity. Usually on such trips, Slowinski carried along the creature comforts he most enjoyed, a boom box and some beer. This time he had only a Discman and some CD's of California punk rock bands. ''This is probably going to be one of the hardest things you have ever done,'' he told his teammates.

It was monsoon season, and the rain was relentless as they climbed up along a mountain. Rivulets cut through the forest trail; the hikers balanced along small bamboo bridges; in vain, they soaked their legs with tobacco juice and even wore nylon stockings to keep the leeches away. Still, Douglas Long, a bird expert, was amazed at the number of rare and unusual birds. Slowinski pressed on in his sandals, shorts, and T-shirt, sometimes passing the others, armed with his Discman and his metal snake-grabbing stick.

It was early on the fifth day -- on Sept. 11, in fact -- when Slowinski was bit. They were at the bottom of a fog-filled jungle valley. Slowinski had reached into a specimen bag that one of the Burmese field assistants had brought him. There is still confusion over who said what about the snake in the bag, but after the bite, Slowinski said, ''I was just bit by a krait.'' It was a juvenile krait, only about a foot long, banded, beautiful, and when everyone looked at Slowinski's hand they could not even see where it had penetrated.

Slowinski waited for symptoms. He ate breakfast with the team, he even joked around. ''My skin's thick,'' he said. But afterward, he began to feel a tingling, and this was when he knew. He called the team together and described what would happen to his body. He told them that while his brain would continue to function, while he would be aware of all that was happening around him, his body would begin to shut down. The venom's neurotoxins would cause paralysis. He told them that they would have to breathe for him if he was to survive the bite; after 48 hours his lungs might restart. ''He laid it all out,'' Long said.

His head began to droop. His eyes began to close, and his diaphragm stopped working. The two women on the team gave him mouth to mouth. He stopped being able to speak and signaled to the team by wiggling his hands or toes: once for yes, twice for no. When a male member of the team tried to relieve the two female scientists, he signaled no -- a little joke that amazed everyone and gave them hope. But eventually, the women were exhausted, and Slowinski was no longer able to signal. The Burmese men helped breathe for their mentor.

Meanwhile, two members of the expedition had run off to a military outpost several miles away. The Myanmar military tried to fly a helicopter into the campsite, but the pilots turned back because of the rain and the fog. The next morning, Slowinski was still alive, but by the afternoon, when the pilots had finally found a way to bring the helicopter down, he was gone.

After a small Buddhist prayer ceremony, Slowinski's body was cremated in Myanmar. His ashes were flown back to San Francisco, where they arrived along with venomous snake specimens, some of which may be Slowinski's last newly discovered species. At the institute where he worked, they hope to name a new venomous snake after him.

Robert Sullivan is the author of "A Whale Hunt."