What did Bartle take with him and what did he do with the items when Captain Anderson arrested him?

When Captain Bartle arrested him, Bartle asked if he could take something with him. The captain told him that it would be taken from him when he got to where they were going. Bartle took Murph and his casualty feeders cards and tucked them in the elastic band of his shorts. As he and the captain crossed the footbridge, he asked if they could stop a moment. The captain allowed him to stop, and Bartlett dropped the two cards into the river.