Heinemann shows116 that lactic acid exists in two optical modifications, the levorotatory and dextrorotary acids.
The gums are translucent, amorphous substances, whose solutions in water are levorotatory.
levorotatory le·vo·ro·ta·to·ry (lē'və-rō'tə-tôr'ē) or le·vo·ro·ta·ry (-rō'tə-rē)
Turning or rotating the plane of polarization of light to the left.
Of or relating to a chemical solution that rotates such a plane to the left.