A colleague who collects old microscopes, early specimen preps, and related
stuff has a item that looks fascinating, but what is it?

Two parallel glass rectangles, the lower about 2 mm thick and about 2.5 x
7.5 cm, the upper about 1 mm thick and about 2 x 7.5 mm, are separated by
three rectangluar glass blocks about 3 mm thick.  One is a narrow
rectangular block set transverse to the long axis equidistant from the two
ends.  The other two blocks are more nearly square and at opposite ends.
The parts are glued together, so that two identical 3 mm thick flat square
chambers exist, separated by the narrow block.   Each chamber is about 2 cm
square.  These chambers are open on two sides (along the long edges of the
7.5 cm long rectangles). On the upper surface of the upper glass rectangle
two etched 1 cm squares are present, one over the center of each chamber.
Each square is divided into 5 equal parts by parallel etched lines
transverse to the long axis of the whole apparatus.  Tap water, when
introduced into the chambers, stays in until actively removed.

If I had to guess, I'd guess it was some sort of paired counting chamber.
Or it might be some divice for observing motility, or something.

If you know what this is, please tell me.

Thank you.

Cusinart Pathologist in Anaheim
Mark Janssen, MD