mammal to substitute for the pigeons then used in beriberi research. they fed guinea pigs their test diet of grains and flour, which had earlier produced beriberi in their pigeons, and were surprised when classic scurvy resulted instead. this was a serendipitous choice of animal. until that time, scurvy had not been observed in any organism apart from humans and had been considered an exclusively human disease. certain birds, mammals, and fish are susceptible to scurvy, but pigeons are unaffected, since they can synthesize ascorbic acid internally. holst and frølich found they could cure scurvy in guinea pigs with the addition of various fresh foods and extracts. this discovery of an animal experimental model for scurvy, which was made even before the essential idea of "vitamins" in foods had been put forward, has been called the single most important piece of vitamin c research. in 1915, new zealand troops in the gallipoli campaign had a lack of vitamin c in their diet which caused many of the soldiers to contract scurvy. it is thought that scurvy is one of many reasons that the allied attack on gallipoli failed. vilhjalmur stefansson, an arctic explorer who had lived among the inuit, proved that the all-meat diet they consumed did not lead to vitamin deficiencies. he participated in a study in new york's bellevue hospital in february 1928, where he and a companion ate only meat for a year while under close medical observation, yet remained in good health. in 1927, hungarian biochemist albert szent-györgyi isolated a compound he called "hexuronic acid". szent-györgyi suspected hexuronic acid, which he had isolated from adrenal glands, to be the antiscorbutic agent, but he could not prove it without an animal-deficiency model. in 1932, the connection between hexuronic acid and scurvy was finally proven by american researcher charles glen king of the university of pittsburgh. king's laboratory was given some hexuronic acid by szent-györgyi and soon established that it was the sought-after anti-scorbutic agent. because of this, hexuronic acid was subsequently renamed ascorbic acid. 21st century rates of scurvy in most of the world are low. those most commonly affected are malnourished people in the developing world and the homeless. there have been outbreaks of the condition in refugee camps. case reports in the developing world of those with poorly healing wounds have occurred. human trials notable human dietary studies of experimentally induced scurvy were conducted on conscientious objectors during world war ii in britain and in the united states on iowa state prisoner volunteers in the late 1960s. these studies both found that all obvious symptoms of scurvy previously induced by an experimental scorbutic diet with extremely low vitamin c content could be completely reversed by additional vitamin c supplementation of only 10 mg per day. in these experiments, no clinical difference was noted between men given 70 mg vitamin c per day (which produced blood levels of vitamin c of about 0.55 mg/dl, about 1⁄3 of tissue saturation levels), and those given 10 mg per day (which produced lower blood levels). men in the prison study developed the first signs of scurvy about 4 weeks after starting the vitamin c-free diet, whereas in the british study, six to eight months were required, possibly because the subjects were pre-loaded with a 70 mg/day supplement for six weeks before the scorbutic diet was fed. men in both studies, on a diet devoid or nearly devoid of vitamin c, had blood levels of vitamin c too low to be accurately measured when they developed signs of scurvy, and in the iowa study, at this time were estimated (by labeled vitamin c dilution) to have a body pool of less than 300 mg, with daily turnover of only 2.5 mg/day. in other animals