Reeling: 1st attempt
I boiled a little water in a pan, and then turned off the heat. After allowing it to cool for a few seconds I added the semi-opaque cocoon. It floated.
I then stirred the cocoon in the water for a few minutes until it leaked, filled with water and sank. I then noticed that some of the cocoon had come away from the rest. I have discovered that this is because a silkworm silk consists of two proteins - two strands of fibroin which are insoluble (the brin), and sericin which glues the two brin strands together. The sericin glue is water-soluble, and some of this dissolved enough for me to catch some of these fibroin strands on my pencil.
Unfortunately, I couldn't get a single thread of silk (a bave = two brin glued together), and resigned myself to pulling away several fibres at once. However, I kept pulling, and found that more and more silk came away from the cocoon until there was only some residual silk left surrounding the pupa. This silk (called the pelade) is slightly different from the rest of the silk in the cocoon and is generally left behind in the reeling process. In cross-section, under the microscope, the silk fibres of the palade look flat, whereas silk fibres of the main part of the cocoon have a circular cross-section. The silk of the outer floss is different again, and is elliptical.
So the silk I eventually wound around my pencil wasn't a single fibre. It was also of variable thickness and fairly short. I am blaming this on the inferior quality of the cocoon and the lazy nature of the silkworm inside, which obviously couldn't be bothered to finish the thing off.
I know this because after I had finished I looked at the 'corpse' inside the cocoon and discovered that it looked like the beginnings of a pupa.
Even though I found this slightly disturbing I have to confess that a small part of me also wondered how it would taste like fried in oil.