The Serpent's Tooth Mystery

This mystery began early one morning at Bayport's Zoo. Joe and Frank Hardy's friend Phil, who was working at the zoo, invited them to see the zoo's newest addition – an Australian Tiger Snake. Before they got to see the snake, it went missing, along with several other poisonous snakes, venom, and anti-venom. Not only that, but the world famous herpetologist, Dr. Harrod Michaels appears to have been bitten by it and is in critical condition. All of the clues lead to Phil as being the thief, but naturally, Joe and Frank discover the real thieves, who include Dr. Michael's assistant. They also figured out that Dr, Michaels wasn't bit by the Tiger snake, but was hit with a dart filled with poisonous venom milked from a different snake. This is one of the later Hardy Boys books which is written in a different style and with more action than the original books.