What doesn't suck in the Early Middle Ages in Europe? Hint: They’re slimy.

 Well, not as much as one might think and certainly nowhere near as much as in the late 1700's to the 1800's.[1]  In the Early Middle Ages, about 500 CE to 1000 CE or so, leeches were not very popular in European medical practice according to the medical texts of the time.  Leeches appear in medical writing in this period in three main ways.  Some writers thought that leeches were just plain bad news.  Others would include leeches as an ingredient in a recipe.  And yes, they were used for bleeding too.

 Leeches could and still can pose their own risks.  Leeches can become lodged in the part of the throat that meets the nasal passages and cause unexplained bleeding of the nose and throat.[2]  Dioscorides, who wrote in the second half of the first century CE, recommended vinegar, on its own or mixed with silphium, as a gargle to remove the leech inconveniently lodged in the throat.[3]  

Ferula tingitana, related to the now extinct Silphium.

Leeches could be useful for far more than just their annoying habit of sucking blood.  Most commonly it was the ashes of leeches burned alive that were used.  The leeches were reduced to ash by being sealed in a rough ceramic jar and placed on a fire.  In a text called The Medicine of Pliny, dated to the third century CE, the author suggested that roasted leech mixed in vinegar and applied to the skin would inhibit hair growth.[4]  This same recipe idea is related in a poem that was popular in Carolingian (c.750-900 CE) manuscripts and attributed to Quintus Serenus. The Book of Medicine related various remedies in one thousand lines of hexameter, the meter of epic poetry. Here is the one for preventing hair (the plucked wood) from regrowing.

nec non e stagnis cessantibus exos hirudo

sumitur et vivens Samia torretur in olla:

Haec acidis unquit permixta liquoribus artus

evulsamque vetat rusus procrescere silvam [5]

“And also, the boneless leech is taken up from the resting pools and living, burned in cheap pottery in oil: This mixed thoroughly with bitter liquids anoints the limb and prevents the plucked wood from growing larger.”[6]

Medicinal leech by Karl Ragnar Gjertsen.

And finally, leeches were used for bleeding.  Blood as one of the humors, the four substances which controlled disease, blood, bile, choler, and phlegm, could be out of balance and cause disease.  The most common type of bloodletting in this period was through the cutting of veins and many Latin texts concerning bleeding survive from the Early Middle Ages.  The texts describe how to draw blood, how much blood to draw and which veins to use. Bleeding was also controlled by the cycles of the moon and special Lunaria or moon calendars suggested when it was best to bleed patients.  Bleeding in specific places treated specific symptoms.  Another way to draw blood was using cupping.  Caelius Aurelianus, who wrote On Acute and Chronic Diseases in the fifth century in Northern Africa, suggested that leeches could be used for bleeding if there was not enough room for the required cups or if the cups were not adhering properly.[7]  Again our friend Quintus suggests that among other options for treating patients suffering from spleen, that the river leech may benefit by sucking gore (proderit exsucto fluvialis hirudo cruore).  

Chapter on Curing those Suffering from Spleen
St. Gallen, Stiftsbibliothek, Cod. Sang. 44, p. 312

In Quintus Serenus' poem, Book of Medicine, leeches are mentioned only three times and blood letting was the reason only once and then then only for the treatment of patients suffering from spleen.

If healers were using leeches more than the texts suggest, there is no way to know.  It may be useful to think about why leeches may not have been popular in the Early Middle Ages.  At the height of the popularity of leeches, they were hard to get in England and expensive.[8]  This should come as no surprise since leeches require bodies of water to live in and must be collected from those bodies of water and transported to where they would be used.  Apparently, they could live for two months packed in straw. Still not a huge window of time considering the length of winter.  In the early medieval period, leeches would have been seasonally available north of the Alps and even then, only depending on certain environmental factors.  The two types of leeches typically used for medicinal purposes are most active at about 21 degrees Celsius water temperature and often will not swim at all below 19 degrees.[9] Weather could affect water temperature and the presence of active, breeding leeches. Local availability and weather could certainly explain why leeches were cited as an option rather than the preferred course of action.  This also explains the use of burned leeches.  The burned remains, if kept dry, could be stored for much longer than a live leech.

 So, while leeches were one of the tools an early medieval doctor could turn to, early medieval doctors chose leeches much less frequently than their nineteenth-century counterparts.[10]

 

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[1] Roy T. Sawyer, “History of the Leech Trade in Ireland, 1750–1915: Microcosm of a Global Commodity,” Medical History 57, no. 3 (July 2013): 420–41, https://doi.org/10.1017/mdh.2013.21.

[2] Wei-Chih Chen et al., “Nasal Leech Infestation: Report of Seven Leeches and Literature Review,” European Archives of Oto-Rhino-Laryngology 267, no. 8 (August 1, 2010): 1225–29, https://doi.org/10.1007/s00405-009-1188-0.

[3] Lily Y. Beck and Dioscorides Pedanius, De Materia Medica, Third, revised edition, Altertumswissenschaftliche Texte Und Studien, Bd. 38 (Hildesheim: Olms-Weidmann, 2017), 340–41.

[4] Yvette Hunt and Kai Brodersen, eds., The Medicina Plinii: Latin text, translation, and commentary, Scientific writings from the ancient and medieval world (New York, NY: Routledge, 2019), 100–101.

[5] Quintus. Serenus Sammonicus and Friedrich Vollmer, Qvinti Sereni Liber Medicinalis, Corpus Medicorum Latinorum, II 3 (Lipsiae et Berolini: in aedibvs B. G. Tevbneri, 1916), 33, ll. 670–674,  http://cmg.bbaw.de/epubl/online/cml_02_03.php.

[6] My translation.

[7] Caelius Aurelianus, Israel Edward Drabkin, and Soranus, On Acute Diseases and On Chronic Diseases (Chicago: Univ. of Chicago Press, 1950), 447–49.

[8] Sawyer, “History of the Leech Trade in Ireland, 1750–1915.”

[9] U. Kutschera and Joy Elliott, “The European Medicinal Leech Hirudo Medicinalis L.: Morphology and Occurrence of an Endangered Species,” Zoosystematics and Evolution 90(2) (November 18, 2014): 271–80, https://doi.org/10.3897/zse.90.8715.  This article also talks about modern pressures which are leading to a large decrease in the medicinal leech population in Europe.

[10] For more about medicinal leeches please read Robert N. Mory, David Mindell, and David A. Bloom, “The Leech and the Physician: Biology, Etymology, and Medical Practice with Hirudinea Medicinalis,” World Journal of Surgery 24, no. 7 (July 1, 2000): 878–83, https://doi.org/10.1007/s002680010141; and N. Papavramidou and H. Christopoulou‐Aletra, “Medicinal Use of Leeches in the Texts of Ancient Greek, Roman and Early Byzantine Writers,” Internal Medicine Journal 39, no. 9 (2009): 624–27, https://doi.org/10.1111/j.1445-5994.2009.01965.x.