Cancer researcher setsup mice for radiation exposure investigations by A. Nettleship and P. Henshaw. The carcinogenesis of urethane (ethyl carbamate or carbamic acid ethyl ester) was discovered in the course of these experiments. Medical researchers use mice for numerous reasons. Mice are small, require little food or housing space, have consistent disease manifestations, have good-sized litters of offspring, are easy to handle, and can be readily shipped from breeding facilities to research locations. Their use as cancer models has provided exceptional insight into the biology of human cancers, and, more recently, their genetics. No photographer credited, dated 1944.