Sorry, it took me some time to have a look at this, but this is an interesting topic worth researching a little!

Latrines and straw

Archeological investigations of medieval latrines in Europe and in the Middle East have indeed found remnants of straw among the many other residues of plant materials, animal materials, and general garbage. The straw residues have been tentatively explained as follows.

Greig (1981), when analysing the "Barrel-Latrine from Worcester" (15th century), thinks that they were floor sweepings. He notes that it was common to discard food wastes - fruit stones, bones etc. - on the floor, and he believes that laying hay, straw and other dry plant materials there served to mitigate the side effects of this practice. Such dry plant material, once trampled, would have helped to "perfume" the premises (Greig, 1994, cited by Costes et al., 2006). Once collected, floor sweepings mixing straw and food waste would have been thrown in the "barrel-latrine". However, he finds this "strange" since the inhabitants could have simply discarded the sweepings outside, so he proposes two other hypotheses: one is that those sweepings were put there to "render the contents of the barrel less offensive"; the other is that they were used in place of lavatory paper (Greig, 1981).

The toilet paper hypothesis has been rejected recently by Yovitchitch (2016), who does not think it very credible, as straw would cause anal itchiness and even injuries, "even with a careful hand" (!). But then the occupants of Greek and Roman latrines did use pieces of ceramic for anal cleaning: these pessoi were re-cut to give smooth angles that would minimise anal trauma but they were still abrasive... (Charlier et al., 2012) In any case, medieval people could use softer material such as oakum, cloth, or moss. The latter, notably, has been identified as a probable wiping material after large amounts of it was found in latrine deposits in sites in Dublin and Oslo. For Yovitchitch, rather than being a medieval toilet sandpaper, straw could have been used instead for scouring the pipes, which would explain why it is mixed with faeces.

Note that straw is not found everywhere in archeological latrine digs: the extensive investigations in the latrines of the castle of Blandy-les-Tours have found a large array of animal and plant residues, but no straw. Instead, the researchers have found ashes, and they make the hypothesis that those ashes were discarded in the latrines to absorb liquids and control the smells (Costes et al., 2006). This is not new: the use of ashes, lime, or charcoal to deodorize latrines has been recorded since the Roman period (Bouet, 2022).

Unfortunately, medieval sources are not very talkative about toilet habits. There was certainly a wide variety of customs across time and space concerning toilet hygiene and odour control, including some using straw. Latrine odour was always a problem: in his studies of hygiene in medieval castles, Mesqui (1992, 1993) presents several methods used by people to control the smells through architectural design: isolation of the closets and of the cesspits from the living areas, separate vents to evacuate the "evil air", covers on toilet seats, etc. There is a bill dated from 1396 for 12 bottles for "water of Damas", an hygenic preparation containing several perfumed ingredients meant to deodorize (or purify?) a queen's privy.

More generally, studies about hygiene in specific areas shows that the smells of human excrements were an ongoing and hard to solve problem in medieval cities. Their regulation was a centuries-long source of conflict between authorities - royal and municipal -, landlords, and the people who collected the night soil, the vidangeurs (see Sabine, 1934 for medieval London, or Leguay, 2015 for medieval France). The London Assize of Nuisance, 1301-1431 includes several complaints about cesspit stench, such as this one where a woman sues a neighbour about this circa 1340. The edict of Charles VI of 1 March 1388 about the "cleanliness of Paris" - actually the lack thereof - expresses "great horror and displeasure" at the amount of "sludge, excrements, rubble, and trash" that Parisians left in front of their houses, and at the diseases caused by their "infection and stench" (Isambert et al., 1824). Such edicts and ordinances, which were supposed to force people to clean up and build cesspits (rather than voiding their chamberpots in the street), were hardly effective, and were repeated regularly until the 18th century (Paulet, 1824). The smell problem - not only caused by excrements, but also by tanneries, slaughterhouses, rendering workshops, and all activities producing smelly offals - was still going on in 19th century Paris, and was not solved until the generalization of the tout-à-l'égout, the "all-in-sewer", ie functional city-wide sewerage collecting systems that eliminated the need for personal or collective cesspits.

What about composting?

People have known for a very long time that mixtures of faeces and other organic materials - including straw and food offals - make great fertilizers and soil conditioners as they enrich the soil in organic and mineral elements. However, the use of human excrements for fertilizers was always debated. Latin authors mostly ignored them, except Columella, even though he talked more about urine than about faeces. (Columella, Book II, XIV)

Second to [bird dung] is human excrement, if it is mixed with other refuse of the farmstead, for by itself it is naturally rather hot and for that reason it burns the ground. Better suited to young shoots, however, is human urine [...] [The husbandman] may sink a trench I directed to be made for the storage of manure, and may heap together in one pile his ashes, sewer filth [caenumque cloacarum], straw, and other dirt that is swept out. [...] I consider those farmers lacking in industry who have from each of the smaller animals less than one load of manure in thirty days, and likewise ten loads from each of the larger ones ; and the same amount from each person, for they can gather and heap together not only the waste matter from their own bodies, but also the dirt which the yard and the buildings produce every day.

Columella was against using human excrements for fertilizing vegetable gardens except when strictly necessary (Book XI, III)

Human ordure, although it is reckoned to be most excellent, should not necessarily be employed except for bare gravel or very loose sand which has no strength, that is, when more powerful nourishment is required.

In his historical monography L'Engrais humain (The Human Fertilizer, 1853), chemist Maxime Paulet noted that the antique reservations about the use of human excrements as fertilizers was repeated in the prescriptive agricultural manuals of the later centuries. Olivier de Serre's influential best-seller Théâtre de l'Agriculture (1600) does not mention them in the chapter dedicated to fertilizers. Police ordinances in Paris in the 17-18th century imposed a minimum three-year storage between the dumping of human faeces in a pit and their use as fertilizer, and forbade their use on crops meant for human consumption and in horticulture, because the lands "fertilized that way only produced grains and vegetables deleterious to health" (ordinance of 16 June 1642, cited by Mauguin, 1876). This did not prevent farmers from using them before the mandated three years. People caught doing that - farmers and vidangeurs - were fined by authorities up to the 1730s. Nevertheless, the use of human excrements was commonplace in the French countryside in the 18th century (Paulet, 1853). A Swiss dictionary of domestic economy of 1770 recommended them in the following fashion (Société économique de Berne, 1770):

The bad smell of human excrement generally causes a great repugnance to its use, although when properly used it is the most perfect of all fertilizers. But by adding a portion of quicklime to it, one makes it lose its stench in a short time, and transforms it into a blackish earth, as fruitful as any fertilizer. By regularly throwing straw into the latrines, we obtain at the end of the year a manure which has lost most of its bad smell.

Note the use of quicklime and straw in latrines for the dual purpose of reducing smells and producing - after a year - a compost valuable for fertilization.

The 18th and 19th centuries saw considerable research and development in organic fertilizers, with farmers and agronomists creating more or less complex "recipes" - some of them called composts - that mixed plant, animal, and mineral materials. Several methods for using human faeces as fertilizers coexisted and were debated in late 18th-early 19th century France, and I will present three of them.

-> Continued