A patent medicine. A chemical teetotal drink containing phosphates and iron that the manufacturers claimed improved the drinkers brain power. http://chestofbooks.com/food/beverages/Drinks-Of-The-World/Aerated-Drinks-Part-3.html

An exclamation or minced oath, expressing vexation, surprise, or other emotion.  Short for Gadzooks [OED]

God's wounds. Used in oaths and asseverations [OED]

A harvester's hook

A workman who refuses to join an organised movement on behalf of his trade; in extended uses: a person who refuses to join a strike or who takes over the work of a striker; a blackleg; a strike-breaker [OED]

Policeman