I would be fascinated to learn more about such activities, if they indeed occurred. I know that British and American officers used smallpox invested blankets to wipe out many American Indians during the French and Indian War (1754-1761). In particular, such blankets were given to the Delaware nation, causing incredible casualties.
However, my understanding is that nearly all white/black people of that era caught smallpox as children. By surviving, they had life-long immunity to re-infection. If this is correct, smallpox would not have been an effective weapon in the Civil War era as it could possibly be today. Am I mistaken?