Abstract: A system for identifying microorganisms and other microscopic particles in a fluid, includes a laser that directs a laser beam (14) through a detect zone (20) and a plurality of photodetectors (30) that detect light scattered in different directions from a particle at the detect zone, and includes a carrier (110) that confines fluid to movement along a narrow path. The carrier includes a glass sphere (112) with a passage (116) for carrying the fluid. The spherical surface allows light scattered at a large angle from the direction of the laser beam, to pass through the glass sphere to its outside for detection there.