By the terms “ankylostomiasis,” “miners' anæmia,” and the “miners' worm disease,” is meant a malady due to the presence in the small intestine of numerous slender worms called Ankylostoma duodenale,—ἀγκύλος, crooked, στόμα, a mouth, and duodenale, because usually found in the upper part of the small intestine. Although the disease is known to have existed for long in Egyptian and Tropical countries, it was not until the huge mining engineering operations connected with the tunnelling of the Alps at Mont Cenis and St Gothard for railway extension were in progress that the disease attracted public attention in Europe. During the piercing of these Alpine heights the parasite was the cause of considerable ill-health and of loss of life among the miners, especially at the St Gothard. For a considerable length of time the true nature of the malady was not recognised. It was owing to the fact that as anæmia was one of the principal physical signs of the malady the disease came to be called miners' anæmia, and as the men worked in tunnels, the term “la maladie des tonnelles” was also given to it. After the discovery of the parasite in the small intestine of affected miners, the designation miners' worm disease came to be applied to it, and it is by this name that it is commonly known in this country.