The Tale of a Nail

Just as those of us obsessed with Franklin's lost expedition were settling in for our nice winter naps, with visions of next year's dives on "Erebus" and "Terror" dancing in our heads, we've been rudely awakened by a fresh scientific study that's making the rounds. Its subject, in fact, is both old and new -- John Hartnell, exhumed from his grave at Beechey Island in 1986, and two samples collected and stored, but not studied until now: one thumbnail and one large toenail. The press stories have tended to vary between thumb and toe in their accounts, but in fact it was both -- and no "clipping" either -- that a team of Canadian scientists used to trace, over a longer period of time than had been possible before, young Hartnell's intake of various chemical elements.

In preparing a voodoo spell, a person's fingernails and toenails are thought to be powerfully efficacious; just so here, science has constructed what the team has dubbed "Hartnell's Time Machine." For, while the visible part of the nail is only of relatively recent growth, the full nail -- from root to tip -- has a longer story to reveal: 19.5 mm in the case of the thumb, 22.5 in that of the toe. Combined, the nails have been used to trace Hartnell's food intake all the way back to June of 1845, just after the ships sailed, through to his death on 6 January 1846 -- nearly seven months. In particular, the team looked at lead, zinc, and copper exposure, as well as at nitrogen stable isotopes. The findings were then compared to a "reference toenail," one associated with a modern individual whose diet included red meat.

The conclusions of the study are fascinating: from the isotopic nitrogen analysis, it was possible to show that, throughout the period, Hartnell consumed no seafood (it's too bad that someone with a knowledge of sailors' eating habits wasn't consulted -- "there needs no ghost come from the grave to tell us this"). As to lead, the results, consistent with other more recent studies, suggest that Hartnell's exposure continued, but didn't increase significantly, during the expedition, though it did rise in the last few weeks of his life, possibly due to his having been given extra rations of tinned food, or some of the "wine for the sick" on board (wine was known for lead contamination at this time). It's also possible that weight loss and illness accounted for the higher relative concentrations. Copper was more of a constant, as was zinc -- though in the latter case, it seems that Hartnell began the expedition and finished it with a severe zinc deficiency. This condition would have increased his susceptibility to illnesses, including TB, and thus could have been a factor in his death. Unfortunately, nails from Hartnell's two grave-mates at Beechey were not available for comparison.

A zinc deficiency could also cause other symptoms -- "depression, anxiety, lethargy, impulsivity and irritability," according to the study. The only remedy would have been fresh meat, which we already know was very scarce indeed; the last time any of the crew would have enjoyed any would have been shortly after arrival in Greenland, when oxen brought on the transports were slaughtered. At the same time, it would be too bad if a zinc deficiency were to be taken -- as, unfortunately, it seems to have been in some press accounts -- as the new "single-explanation" theory. The lack of fresh meat, and conditions of the sailors, on board Franklin's ships would have been very similar to other British naval expeditions of the day, none of which suffered the catastrophic losses of Franklin's, and indeed a recent study (one of whose authors was the late William Battersby) suggests that other causes -- accidents, exposure, scurvy, tuberculosis, and other respiratory conditions -- played a far more prominent role, on the whole, in Arctic expeditions of the period generally. So this new study, while certainly welcome, doesn't necessarily change our prevailing understandings.

The curious can consult the full study here -- it's available for purchase, or can be had via the libraries of subscribing research institutions.