Does The Medicinal Leech Still Exist In Blarney Lake?

Blarney Lough, County Cork 

William Molyneux (1656-1698), influential Natural Philosopher from Dublin, asked the onetime Military Governor of Cork, Richard Cox (1650-1733), for a description of Cork and its environs as a contribution toward a proposed “Natural History of Ireland” (a work which was never published). In his response written about 1685, Cox included the following snippet: “Blarney, a very strong castle and a noble seat of the Earle of Clancarthyes within 3 myles of Cork, in a large park well furnished with wood and water and particularly a large lough abounding with leeches”.

65 years later, in 1750, physician and natural historian Charles Smith (1715-1762) corroborated the presence of medicinal leeches here (Smith 1750: I, 169,170; II, 323,324): “This castle [Kilcrea] is seated upon an eminence, with a river running beneath it, and on the other side is a fine lake of about thirty acres, abounding with quantities of good leeches […] Adjoining to the castle, is a fine park, sweetly wooded, and well watered; also, a fair bridge over Blarney river. The gardens of the castle are well laid out, and kept in good order […] In this wood, are quarries of limestone […] The common leech abounds in the lough of Blarney, from whence Cork and Dublin may be supplied with them…”

In this context the Irish poet, Richard Alfred Milliken (1767-1815) wrote, a poem in 1796, “The Groves of Blarney”, which makes reference to its leeches, quoted here in part (Milliken 1900: 9):

“Tis there the lake that is stored with perches,

And comely eels in the verdant mud;

Beside the leeches, and groves of beeches,

All standing in order for to guard the flood.”

Somewhat later, in 1813, the Rev James Hall confirmed first-hand that some sort of leech did live in the Lough of Blarney at that time (Hall 1813: 196-197): “The lake of Blarney, about a mile in circumference, so abounds with perch, roach, eels, and other fish […] This lake is also so full of leeches, that, if any person put in his foot, or his arm, it will soon be black with them. Two young gentlemen lately went thither, it seems, to bathe; but, before they were many minutes in, finding themselves attacked by they knew not what; they hastened to the shore, and found themselves completely black with leeches; which, as fast as possible, they rubbed off one another’s back, after they had cleared the other parts of their body. I put my hand into the water, to try whether I could discover any, and in less than a minute found some of them appearing.”

In 1824 another visitor claimed that leeches were still here, presumably basing this on locally acquired knowledge: “A short distance to the south west of the castle is a lake, said to abound with a species of leech” (Croker 1824: 306). Later still, in 1839, a meticulous history of the Cork region stated that the lake, “abounds in leeches, not prized however for their medicinal utility” (Windele 1839: 210). There is no evidence for the speculation that the medicinal leeches historically documented at Blarney Lough were imported and stored in the lake.

I sampled briefly for medicinal leeches at Blarney Lough in August 2012 using the traditional wading technique. On this occasion no medicinal leeches were found in the lake which was otherwise rich in aquatic invertebrates, but another bloodsucking species Theromyzon Philippi, 1867, was remarkably abundant, as were its prey hosts, swans and geese. One potentially relevant observation is that at least two adjacent herds of cattle are currently fenced from entering the water of the lough, barring leeches from its main historic food source. Undoubtedly, farming practice in mid-19th century allowed cattle here to roam freely into the water. Still, a small population of medicinal leeches could subsist in Blarney Lough or other Irish sites on frogs and aquatic birds, as is known in similar sites on mainland Britain.

Searching for the medicinal leech at Blarney Lough, the last known home for this species in Ireland. The traditional technique by which this bloodsucking species attaches to a wader’s legs is much recommended over the more frequently used shoreline netting. The concentric motion waves direct this swimming species to its potential host. An additional technique for finding the medicinal leech is to look for them amongst spawning frogs in the spring.

Historical evidence for the presence of medicinal leeches in Ireland predates by up to hundreds of years their importation for medicine starting from about 1750. Furthermore, there can be little doubt that medicinal leeches did live in the wild as late as mid-nineteenth century. Nonetheless, in the final analysis the majority of the historical accounts outlined above are secondary, essentially hearsay sources. In this context the account by Rev. James Hall in 1813 at the Blarney site is remarkable in being record of a first-hand experience. He clearly described an active leech with aggressive behaviour which is definitely not that of the sluggish “horse leech”. It is persuasive, also, that the contemporary use of Irish collected leeches was claimed explicitly by some of Ireland’s most eminent medical practitioners and apothecaries, including John Rutty, Michael Donovan and William Wilde. In his capacity as foremost apothecary in Dublin, Michael Donovan clearly stated that the decline of Irish leeches was gradual and their unavailability was relatively recent. To meet increasing demand for leeches in contemporary medicine, they had to be imported into Ireland from abroad. This decline in local sources parallels the experience in mainland Britain, France and other parts of western Europe.

To counter the high price of imported leeches Donovan proposed in 1849 that a leech farm be established in Ireland. Such an enterprise was established briefly in 1852 near Callan by a French firm, but there is no evidence that it was successful. In fact, there is no evidence that imported medicinal leeches ever established themselves successfully anywhere in Ireland, in spite of speculation to the contrary. As discussed in the introduction, nowhere in the British Isles has it been shown that Hirudo medicinalis established itself in the wild, in spite of the millions of specimens imported into Britain and Ireland in the 19th century. Consequentially, the speculative assumption that medicinal leeches once found in the wild in Ireland were alien escapees must be rejected as unfounded.

In any case, no medicinal leeches are known to live anywhere in Ireland today. In 1895 the very experienced Irish naturalist Robert F. Scharff (1856- 1934), Director of the Natural History Museum in Dublin, wrote “I have not seen an Irish specimen, but it is quite probable that it does occur in this country”. A few years later he was more pessimistic: “I have never seen an Irish medicinal leech, and my efforts to get a specimen have hitherto proved fruitless”. More recently, in his comprehensive study of Irish leeches Kieran McCarthy observed “…nor have I succeeded in collecting specimens there [Lough Mask] or elsewhere in the country” (McCarthy 1975: 413).

All efforts to locate voucher specimens of native Irish medicinal leeches were unsuccessful (this highlights the urgent need for voucher specimens of medicinal leeches from localities throughout its current range). No Irish specimens are known from natural history museums and medical institutions.

A single specimen in the Natural History Museum in London is recorded “with the locality ‘Dublin neighbourhood’. No date. Unregistered, but it was in the Old Collection (i.e. it was in the British Museum before 1881, when it was transferred to the Natural History Museum in South Kensington). Unfortunately, such a specimen may have originated from a Dublin pharmacy or doctor who had imported it for medical purposes, there being no evidence it was collected in the wild.

Scrupulous efforts were made to distinguish “leech” meaning the bloodsucking animal from “leech”, an Anglo-Saxon term meaning doctor or healer. In early literature of Ireland in the English language the latter term was in common currency at the time. For example, the paper, “The leech in ancient Ireland”, deals exclusively with early medical practitioners and does not mention the bloodsucking animal at all (Binchy 1952).

The above article, is an edited version by Chris Synnott, with the author’s permission, of a longer and more scientifically-rigorous paper written by Roy T. Sawyer, Medical Leech Museum, Swansea, which appeared in ‘Old Blarney’ Journal Issue No. 9.

Contact: Mr. Brian Gabriel Email: Tel: 087-2153216