Besides food, spare clothing and shelter, the men had lost a good and true friend in Ninnis. Mertz, who had shared dog-handling responsibilities with Ninnis, had also lost most of his canine friends, and as a vegetarian now faced the prospect of eating the remaining dogs to survive. The journey home did not hold much promise.

The remaining two weeks of 1912 were an increasing struggle as men and dogs fought increasing weariness and hunger. One by one the dogs, whose food had been lost on Ninnis’ sledge, became too weak to move. With already-meagre rations dwindling, the weakest dog was shot, cut up and eaten — a process repeated until no dogs remained alive.

On Christmas day the men had covered nearly half the distance home, and by 6 January 1913 they were over two-thirds of the way there. But little by little, Mertz was getting weaker and losing spirit, finally refusing to move. With Mawson tending him, he fell into a fever. ‘His heart seems to have gone,’ Mawson wrote in his diary.

The next day Mertz agreed to be hauled on a sledge by Mawson, but he was too ill to move. Mawson tended him in the tent, through an agonising day of good travelling weather. Then, at 2 o’clock on the morning of 8 January, he died.

Mawson guessed in his diary that Mertz had died as a result of ‘weather exposure & want of food’. He later added that colitis (inflammation of the colon) may have been the cause. In 1969 a medical analysis concluded that he died from eating too much dog liver with its high concentrations of Vitamin A, which can be toxic to humans.