What kind of glue is used for ancient furniture?

In ancient times, nails, buttons and other gluing tools were refused to be used in furniture making, and furniture lost its stability only through the combination of tenon and mortise, so ancient craftsmen also needed gluing when making furniture, but unlike the chemical glue used in modern homes, the adhesive for furniture in Ming and Qing Dynasties was bio-glue. It is artificially refined by using the gum of animals and plants themselves. One common glue is fish maw swim bladder, and the other is pig maw swim bladder.