He travelled; stirring thus about his feet
The waters of the pools where they abide.
‘Once I could meet with them on every side;
But they have dwindled long by slow decay;
Yet still I persevere, and find them where I may.’
In Europe, where the leech was once very abundant, it is now chiefly confined to the south and east, and in Germany it is still found in the island of Borkum and in Thuringia—but just now we need not trouble ourselves very much about their distribution in Germany.
In 1842, leeches were occasionally found in the neighbourhood of Norwich, and there are villagers still living in Heacham in Norfolk who remember the artificial leech-ponds. In the middle of the last century the medicinal leeches ‘of late years ... have become scarce.’ At about the same time, it is also recorded that they were becoming scarce, though still to be found, in Ireland. Apparently this species is now almost extinct in England, although I know of a naturalist who can still find them in the New Forest, but he will not tell where. If they were getting scarce in the beginning of the nineteenth century they are far scarcer now[14]—for there is no leech in London—at least, there are only a dozen or two, and they, like those of the firm ‘Sawyer late Nockemorf,’ are second-hand and I have heard that there is a similar shortage in North America. And yet leeches are wanted by doctors!
Harding tells us that:—
Hirudo medicinalis is not the only leech which has been used in phlebotomy. Hirudo troctina (Johnson, 1816), occurring in North Africa and in Southern Europe, where it is perhaps an introduced species, was largely imported at one time for medical uses....
Several other species have been used for blood-letting in different countries. Limnatis (Poecilobdella) granulosa in India, Liostoma officinalis in Mexico, Hirudo nipponia in Japan (Whitman), and Macrobdella decora in the United States (Verrill), are or have been used in phlebotomy.