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posted by Fnord666 on Wednesday August 15 2018, @02:37PM   Printer-friendly
from the anthropological-science-FTW dept.

The diet and eating habits of earlier civilizations has been inferred from old manuscripts and artwork, but there is always a question as to how representative that is of what the common diet was at the time, in much the same way as whether in a millennia from now one could infer our modern-day diet from surviving ``foodie'' magazines. It is always a bonus when you can have access to direct tissue to analyze. In a recent paper in the Open Access journal Nature Scientific Reports, Atsushi Maruyama and colleagues in Japan acquired a number of book sets produced during the Edo period and they analyzed samples of human hair found in the books. By analyzing the abundances of various carbon and nitrogen isotopes they were able to make inferences about the early Japanese diet.

The covers of such books are made of recycled thick paper, which, for financial reasons, was believed to have been produced soon before book printing, using waste paper collected in the same cities where the books were printed. Because the hairs are embedded in the paper fibres, the hairs are thought to have been mixed accidentally during waste paper collection or blended intentionally for reinforcement during paper production. In either case, the hairs most likely belong to people living in the city and year of book printing, both of which are available from the records (colophon) on the book. Thus, the hairs found in each book, together with the records of time and place, constitute the ideal human tissue samples to reconstruct the eating habits at the time and place of the book printing, using isotope analysis.

They found that people depended upon rice, vegetables, and fish more exclusively than contemporary Japanese people. They also noticed that the levels of nitrogen increased over 200 years, indicating an increase in the contribution of marine fish as both food and fertilizer, which generally confirms what literature-based studies have found.

Atsushi Maruyama, Jun'ichiro Takemura, Hayato Sawada, Takaaki Kaneko, Yukihiro Kohmatsu & Atsushi Iriguchi, Hairs in old books isotopically reconstruct the eating habits of early modern Japan, Scientific Reports volume 8, Article number: 12152 (2018)


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  • (Score: 2) by AthanasiusKircher on Wednesday August 15 2018, @04:49PM (5 children)

    by AthanasiusKircher (5291) on Wednesday August 15 2018, @04:49PM (#721840) Journal

    Not trying to condescend, but asking rhetorically: do you understand how paper holds together in the first place?

    I do understand how to make paper. You might read my last couple sentences of my last post:

    And wouldn't it make more sense to use -- I don't know -- some other fibrous material found in so many other plants, rather than gathering human hair?

    In response to your assumption:

    And this was before material science, so it was probably the result of people doing trial by error, and finding out hair could make your paper better.

    The dates for this sort of manufacturing apparently went into the 1890s. This wasn't some ancient practice. Making paper from recycled fiber had become common in Europe since at least the late 1400s (probably earlier in China, though I don't know as much about Asian paper production, but paper had been produced in Japan for at least a millennia before the books discussed in this study), and though Japan was backward in some technologies and it took a long time to diffuse ideas, I find it hard to believe they didn't understand paper recycling processes even at the beginning of these hair samples (late 1600s).

    Again, there are plenty of other fiber sources available. Recycling various fibrous materials to make paper has been known for a very long time. Hence my question: why human hair (which is likely harder to collect and definitely harder to grow)?

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  • (Score: 2, Informative) by Anonymous Coward on Wednesday August 15 2018, @05:03PM (4 children)

    by Anonymous Coward on Wednesday August 15 2018, @05:03PM (#721846)

    Probably they didn't seek out human hair, but bought all fibrous waste materials they could? If someone saw a bit of profit in collecting hair from all the barbers in the city, I bet it would happen. I imagine old clothing and many other products were also used, the sole condition being that they are price competitive with standard paper making materials.

    • (Score: 1, Interesting) by Anonymous Coward on Wednesday August 15 2018, @05:13PM

      by Anonymous Coward on Wednesday August 15 2018, @05:13PM (#721847)

      I was thinking this as well - it's garbage otherwise, so why not throw it in? Plant fiber is useful for other things, especially to an island nation. One thing you need a lot of when dealing with fishing/ships is cordage.

    • (Score: 2) by AthanasiusKircher on Wednesday August 15 2018, @05:19PM (2 children)

      by AthanasiusKircher (5291) on Wednesday August 15 2018, @05:19PM (#721851) Journal

      That's a more reasonable reply, though it raises the question of why this practice was not more widespread elsewhere.

      Yes, everything was recycled in old times. (And subsequent searches have told me that Japan apparently started requiring paper recycling in the eleventh century, so they obviously had a lot of time to perfect the process before these samples in this study.)

      And by the way -- as for "old clothes" -- yes, obviously. Before the mid-1800s this was actually a PRIMARY source for paper-making, with old rags and clothes being primarily recycled to create paper. Wood pulp as a major source for paper is a very modern development.

      • (Score: 3, Interesting) by AthanasiusKircher on Wednesday August 15 2018, @05:28PM (1 child)

        by AthanasiusKircher (5291) on Wednesday August 15 2018, @05:28PM (#721855) Journal

        Oh, and for those who don't know this: fun fact, but the more common wearing of underwear was largely responsible for the growth of mass paper and book production in Europe. In big cities in medieval Europe, people started wearing underwear more frequently, which was considered more disposable (originally its purpose was to protect outer clothing). Hence more rags thrown out. Hence more paper. Hence more reading (and then the Renaissance and Reformation and Scientific Revolution and all that... Due to increased literacy and paper availability).

        I mean it wasn't just underwear -- it was an excess of clothing in general that was then scrapped. But that was why paper finally came to dominate in Europe over animal skin parchment... Due to availability of sufficient paper source materials from recycled clothing.

        • (Score: 2) by legont on Thursday August 16 2018, @12:48AM

          by legont (4179) on Thursday August 16 2018, @12:48AM (#721978)

          At he same time, at least in Europe, people stop washing themselves because outwear was protected from bodily fluids and such. Basis of knowledge has really dirty roots.

          And yes, it answers the question were the hair came from in such strange quantities.

          --
          "Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.