"Disappointed we lie down and and consider whether we couldn't have a go at the iron rations"

The iron ration, introduced in 1907, consisted of an emergency food tin for use by military forces when normal food sources were disrupted. 

The German iron ration contained:

250g (8.8 oz) biscuit; 200g (7 oz.) preserved meat or 170g (6 oz.) bacon; 150g (5.3 oz.) preserved vegetables; 25g (9/10 oz.) coffee; 25g (9/10 oz.) salt.