Answer to What is This on the Cover of American Laboratory January

The image on the cover of the American Laboratory January 2013 issue shows benzidine crystals in polarized light. The specimen was fast chilled after melting and squeezed under coverslip pressure. The image was captured using polarized light (crossed polars with ¼ wave plate) at 250× magnification. Benzidine, a carcinogen, was once used in the production of dyes and for the detection of blood. Image captured by Mark H. Armitage (Biology Department, California State University, Northridge, CA).

Congratulations to JAMuckley, this month’s winner of the $10 Amazon gift card.