Because the silk and cotton aren't sewn together, you can see the inside of the bodice. The silk is folded to the inside, so there's a double layer where it's gathered.
The cotton batting is sewn in without any covering. It's about 1/4" thick and covers the entire bust area.
On the left, a detail of the armsyce. The seam allowance is rather narrow and it's was finished with overcasting. On the right, the hooks and eyes. There's a seam just to the right of the hooks, which helps them lie flat.
Details of the cuffs. On the left, the line where the top of the puff is stitched shows clearly. About halfway down, you can see the line of small stitches that marks the center of the puffs. On the right, you can see the piping that finishes the sleeve between the silk and lining.
The underarm seams. These are very wide, and have boning channels stitched into them.