It says that Schmidt was bitten when he took the snake out of the cage. In fact, this snake was examined by a colleague of Schmidt at that time. Scholars who often deal with snakes know which part to catch, and no one can catch the head of a snake. This colleague is holding the safe part of the snake neck. Schmidt wanted to take the snake from his colleague and observe it carefully, but he didn't know why. Maybe he is absent-minded. He didn't hand over in the usual safe way, but accidentally caught the back of the part held by his colleague and was bitten by a snake on the root side of his left thumb.