Unless you’re a marine biologist, the chances are that you’ve never used the word ‘lithophagus’. You may have eaten one, however: Lithophaga is a genus of mussels, some of whose species are edible, often served in a garlic, white wine and parsley sauce with plenty of crusty bread. Delicious.
But I digress.
‘Lithophagus’ comes from two Greek words: λίθος, meaning ‘stone’, and φᾰγεῖν, meaning ‘to eat’. Lithophaga mussels are so called because they have the unusual ability to bore through solid rock. When first observed in the eighteenth century they were believed to be eating it; we now know that they actually have special glands which secrete a chemical which helps dissolve calcium compounds.
Doctors are – or used to be – notoriously fond of unnecessarily long words, and in a case published in the London Medical Gazette in 1839 I found this gratuitous use of ‘lithophagus’ applied to a person – although to be fair it was a patient who genuinely ate stones. 
Dominique Henrion was born at Metz, in 1761. Being but little pleased with the occupations to which he was put when young, he began, at the age of twenty-two, to swallow pebbles.
Well, that’s one way of coping with boredom.
Sometimes he took them whole, and without any preparation; sometimes he broke them between his teeth, after having reddened them in the fire, and then suddenly plunged them in cold water. By this means he passed himself off as a savage from America. (!)
Because, as we all know, what ‘savages from America’ do is eat pieces of rock.
Several years since, he had fixed his abode at Nancy, and there continued the same kind of life, swallowing every day a greater or less number of stones, which on some occasions amounted to thirty or forty. The largest were of the size of a large nut, but they were commonly smaller, and Henrion used to demonstrate their presence in his stomach by the noise they made when he struck his epigastric region.
A charming party trick.
He passed them by stool in twenty-four hours after taking them, and often made use of them again next day.
This does not sound terribly hygienic. At least putting them in the fire would have sterilised them, I suppose.
He swallowed also live mice, but only one a day, as well as moderate-sized crabs, after having cut off their claws.
Not terribly fair. If you’re going to swallow a live crab, at least give it a fighting chance.
As to the mice, when they were put into his mouth, they at once rushed into the pharynx, when they were soon suffocated, and the deglutition [swallowing] of them was then facilitated by that of a stone. The next day they passed from the rectum, with their skins destroyed, and covered with mucus.
Charming. Was this patient actually an owl?
This man continued the same kind of life up to the 1st of April, 1820.
Which means close to forty years of swallowing pebbles.
At that time, after having filled his stomach with a considerable number of stones, he swallowed, for a small sum, a tinned iron spoon, five inches and a half long, and an inch broad. Some hours after, he was seized with vomiting, which continued to the time of his death. He first vomited bilious substances, and then fluid tinged with blood, and of a very fetid smell.
On April 6th 1820 M. Henrion was taken to the hospital in Nancy, where Dr Neret examined him.
The vomiting continued; the thirst was excessive; the pulse small and irregular; the abdomen hard, distended, and painful, especially beneath the umbilicus. Next day, after an enema, the patient passed five stones by stool, but he grew worse, and died on the following day, aged fifty-nine.
An autopsy was performed. Inside the man’s brain the surgeons found a few hydatids – cysts containing tapeworm larvae. Though these would doubtless have caused him problems had he lived longer, they had not apparently contributed to his death.
On opening the abdomen, the stomach was found distended with gas; the great omentum was inflamed, and there were points of suppuration on its anterior surface, as well as on the transverse arch of the colon.
The great omentum is a large apron of fatty membrane which hangs down from the stomach. The intestines also appeared to be inflamed.
On raising the great omentum, an aqueous fluid flowed out, in which there flowed out globules of oil, which appeared to be the medicine that the patient had taken, and which indicated a perforation of the intestinal canal.
Sure enough, the fork was soon detected in the small intestine, and had punctured the wall of the gut. With intestinal contents spilling into the abdominal cavity, it was only a matter of time before peritonitis – massive infection – set in.
There were thirty-two pebbles in the great cul-de-sac of the stomach, with liquid and oily fluids; some stones were also found in the duodenum, and in some other parts of the intestinal canal; the caecum contained five; so that the whole number found in the course of the digestive tube was fifty-three, and they weighed altogether one pound and three ounces.
Some of these pebbles were long and sharp, others long and thin; ‘but in general’, remarks Dr Neret, ‘they did not appear to have been chosen to prevent the wounding of the intestinal canal.’
Fifty-three stones in the digestive tract is fifty-three too many. Even so, after lifetime of swallowing pebbles it was a single spoon that killed him.