MIT Institute Archives & Special Collections

Report: "On the Making of Silk Purses from Sows' Ears," 1921


Image of the silk purse


In 1921 the management of Arthur D. Little, Inc., of Cambridge, Mass., issued a small report describing the methods employed by the firm's chemists to create "silk" from pork byproducts. The idea behind this surprising and not very practical experiment was to prove that something said to be impossible was, with sufficient effort and ingenuity, attainable. As the report notes, the old adage "you can't make a silk purse of a sow's ear" had been used for years to discourage inventiveness and enterprise. "We prove that it was false, and we have done so. We have made a silk purse of a sow's ear."

The chemists' first step was to observe the production of silk by silkworms, analyzing both the process and the product. They found that the viscous liquid emitted from ducts in the worm's head turned to silk after contact with air and that it was chemically akin to glue. Following this lead, the lab reduced one hundred pounds of sows' ears (certified to be authentic by an affidavit from the supplier, Wilson & Company, meatpackers in Chicago) to ten pounds of glue, which was turned to gelatin by adding small amounts of chrome alum and acetone. After much trial and error the chemists hit upon a means of producing fine strands by filtering under pressure and forcing the substance through a perforated spinneret. The resulting brittle strands, softened by bathing in a glycerin solution, were dried, dyed, and woven into cloth of "the desired soft, silky feel." From this cloth two "silk" purses were cut and stitched in imitation of a medieval design.

The company freely acknowledged that the two "silk" purses, expensive to produce, had more value as conversation starters than as items intended for practical use. They were widely exhibited at trade shows and promotional events. "We frankly admit," the report states, "that it is not very strong or very good silk, and that there is no present industrial value in making it from glue." The report concluded:

Things that everybody thinks he knows only because he has learned the words that say it, are poisons to progress. The only way to get ahead is to dig in, to study, to find out, to reason out theories, to test them...

This making of silk purses of sows' ears was merely a diversion of chemistry at play. When chemistry puts on overalls and gets down to business, things begin to happen that are of importance to industry and to commerce. New values appear. New and better paths are opened to reach the goals desired.

Arthur Dehon Little (1863-1935) attended MIT as an undergraduate student in chemistry from 1881 to 1884 and taught papermaking at the Institute from 1893 to 1916. He served on the visiting committee for MIT's departments of chemistry and chemical engineering and was a life member of the MIT Corporation. The firm he founded in 1909, Arthur D. Little, Inc., was for many years one of the largest and most diversified consultancies in the world.

“On the Making of Silk Purses from Sows’ Ears” is included in the Arthur D. Little, Inc. Archives Collection (MC 579), which was given to MIT by the Arthur D. Little, Inc. Alumni Association in 2002. The collection is available for research in the Institute Archives & Special Collections, 14N-118. During the month of October one of the two silk purses is on display in the Maihaugen Gallery with other objects from the collection or lent by alumni. (The other silk purse is in the Smithsonian Institution.) More information about ADL, Inc. and the collection is on the Archives web site.

Object of the Month: October 2001; October 2008

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