I don't know a whole lot about microphotography--or about blood cells either, really!--but I know that this is a microphotograph (a photograph taken under a microscope) of blood, and that is was produced by Dr. S.W. Fletcher of Pepperell, MA c. 1870. (Included in documentation is another from the set this came from, that one mounted with printed attribution on the board.) I've learned that William Henry Fox Talbot (1800–1877) was taking photographs through a microscope as early as 1837, but it was really in the second half of the 19th century, first in Germany, that technologies (apparatus) for taking microphotographs developed. Dr. Samuel W. Fletcher (1830-1910), a distinguished Civil War surgeon, seems to have been a very early American example of a doctor to use it, upon returning to Pepperell after the war. Quite a rare and special feeling thing, which I find extraordinarily beautiful and evocative. This one I especially love for the way the the curve of the lens frames the cellular view along the upper left edge.
11" x 8" as mounted. Photo measures 6 3/8" x 6 1/4". Very good antique condition, with light scattered spotting/toning as documented. The best sort of subtle, and really gorgeous.