I keep an eye out for hidden mother portraits--antique photos in which the mother of a young child is present, unusually in order to prop up or comfort the child, but either veiled (often in the most wonderfully absurd ways) or only partially in the frame. Here I assume it is the mother's hand and arm at upper left, clutching what appear to be a few flowers and I'n not sure what all. On the other hand, this child does not look especially full of life, so perhaps those are flowers of mourning? A bit of a mystery, which I find quite intriguing, and formally love the rightward lean of the baby countered by the left-turning bent elbow of the arm about. On reverse the paper label of T.S. Estabrook, Brooklyn, which from what I've found was active in the 1870s, making this an early one.
3 13/16 x 2 7/16. There is a bend that runs diagonal near top as evident, which is less evident if pressed flat behind glass. Viewed in a certain light, it is clear that a photographer's mat once overlaid this just framing the face and upper body of the child.