It's so hard for me to say to no to an antique gift! So I said yes. I think super fragile pieces like this still have value in the "study collection" realm, as examples of clothing construction techniques of the past.
My friend and I guess the dress and pantaloons would probably fit a three-year-old. The pantaloons are cotton, with woven stripes towards the bottom. They have shoulder straps and a completely open crotch.
I tested the fibers in the dress. It appears to be a silk-wool blend, wool for the horizontal color bands, and silk for the finer, cream colored vertical threads. The bodice lining is either cotton or linen.
There is lovely detailing on both pieces. The waist of the dress has a double row of gathering stitches, which creates a little puckered band, and a corded piping trim.
The neckline and sleeves are finished with a silk binding. The neckline binding also covers a string that maybe once gathered up the neck line to fit more closely.
There are three buttons at the back. These are a more modern replacement, but actually quite cute.
All sewing is hand stitching. The hem looks like it may have had something like a seam tape made of a woven blue gingham.
The cuffs of the pantaloons have a lovely ruffle, gracefully attached with an openwork stitch. The bottom of the ruffle is finished with a 1/8" hem. The edges of the crotch opening are also narrowly hemmed. Again, all the stitching is by hand.
The lining of the dress sleeves is a c. 1860 print. This could be a scrap that is older than the dress itself, but I'm guessing it's not much older. The colors of the plaid and the style of the outfit also point to that time period.
It's just totally adorable, and I can so easily imagine a cute, pudgy little one running around in it!