A New Rotary Microcompressor

A new rotary microcompressor is described and compared with the rotocompressor invented by A. A. Schaeffer. The present instrument allows delicately controlled compression of microorganisms between a standard coverslip and slide with negligible shear forces. The low profile design permits turreting to higher power objective lenses without refocusing. The compression plate with affixed coverslip is prevented from rotating by two precisely positioned rods in the baseplate that holds the glass slide. A reduction gear with graduated scale is turned by thumb wheel to raise and lower the coverslip relative to the glass slide. Slide preparations can be changed rapidly by releasing the four tight-fitting retaining clips holding the compression plate and reduction gear to the baseplate. The Spoon Microcompressor is designed to gently slow and stop swimming organisms, compress organisms to a set thickness and thus determine biomass, and compress soft-bodied organisms so that their internal structures, including ingested food, can be better seen.