Those are silk cocoons, spun by silk worms who have fed long and well on mulberry leaves. There is a fire beneath the caldron, and this lady is boiling them in water to make the very end of the strands loosen, all the while stirring the water so that the strand ends will adhere to the stirring stick. The ends are attached to a spindle and wound, and voila, ready to dye and weave.
Now they have gigantic automated factories to do this work, of course, but this is the way they would have done it back in Johanna’s day.
Everything Under the Heavens in audio download:
The Silk and Song slideshow is here, and I’m going through it a slide or two at a time, with commentary, most Tuesdays here.