For almost 80-years a large triangular slice of Phar Lap's heart has been missing.
Scientists took it in the 1930s to try and work out what killed the chestnut champion in his prime, and what made him one of the most remarkable racehorses the world had ever seen.
National Museum of Australia Director Dr Mathew Trinca says what then became of the specimen has been a puzzle.
"We considered, as almost everybody else did, that the piece that was missing from the heart that we have on display in our Landmarks gallery, was destroyed had been lost in the midst of time,” he said.
That was until curator Natalie Ison found herself in the deep dark recesses of the archives preparing for a new exhibition on horses called Spirited.
National Museum of Australia Senior Curator Dr Martha Sear says Ms Ison did something probably no one has done for many, many years – to slightly tip the jar so that she could have a look at the bottom of it.
“When she did that she saw a label and on that label were the words that listed the anatomical parts that were in the jar. And the final word of the label, which is quite disfigured was the word 'lap'. It' s a moment that will, I think, live in our memories forever."
The museum's Dr Kirsten Wehner was with Dr Sear when a picture of the newly discovered label was emailed through.
"It said “aorta, pericardium, part ventricle wall,” a little bit missing, then "lap". And we both looked at each other and I do believe I may have said 'oh my goodness I think that's part of Phar Lap,’" she said.
Dr Sear says the museum has since been working to confirm the specimen does in fact make Phar Lap's heart whole again.
She says DNA testing is likely to be out of the question, because the formaldehyde that's been used to preserve the specimen would have destroyed all traces of genetic material.
But she says they're exploring other ways of confirming its origin.
"We've removed the specimens from the jars and started to reassemble the ventricle components which form a triangle which we think matches the triangular specimen that is Phar Lap's heart. And we've also spoken with an equine anatomist who confirmed that the aorta, ventricle and pericardium components could have come from the larger heart specimen," she said.
Phar Lap was a New-Zealand-born, Australian-trained thoroughbred who became a household name in the depression years between World War One and Two.
In the space of three years Phar Lap won 36 out of 41 races, including the Melbourne Cup and two Cox Plates.
He was considered a source of national pride in grim economic times and what caused his sudden death in the United States in 1932 has long been a source of great speculation.
So while the National Museum may have put the missing pieces of Phar Lap's heart back together, Dr Sear says just how he came to ingest a fatal dose of arsenic may never become clear.
"Whilst we will continue to learn more about Phar Lap it's possible that that mystery will remain unsolved," she said.
