Trench foot
Trench foot can be prevented by keeping the feet clean, warm, and dry. It was also discovered in World War I that a key preventive measure was regular foot inspections; soldiers would be paired and each made responsible for the feet of the other, and they would generally apply whale oil to prevent trench foot. If left to their own devices, soldiers might neglect to take off their own boots and socks to dry their feet each day, but if it were the responsibility of another, this became less likely. Later on in the war, instances of trench foot began to decrease, probably as a result of the introduction of the aforementioned measures; of wooden duckboards to cover the muddy, wet, cold ground of the trenches; and of the increased practice of troop rotation, which kept soldiers from prolonged time at the front.
Trench coat
A trench coat or trenchcoat is a coat variety made of waterproof heavy-duty cotton gabardine drill, leather, or poplin. It generally has a removable insulated lining, raglan sleeves, and the classic versions come in various lengths ranging from just above the ankles (the longest) to above the knee (the shortest). It was originally an item of clothing for Army officers (developed before the war but adapted for use in the trenches of the First World War, hence its name) and shows this influence in its styling.