The Biology Division of the Oak Ridge National Laboratory ducted with very large numbers of mice, and mice proved to was organized in 1946 for the purpose of studying the imme­ be especially suitable for cancer induction studies. diate and long-term implications of man's exposure to ioniz­ As this work progressed, we became convinced that a ing radiation. The program that developed concentrated on strong histology department was needed to prepare the tis­ the basic mechanism of the effects in biological organisms sues in a uniform manner and also to examine and interpret from the genetic, biochemical, biophysical, and molecular bio­ them. With the support of Dr. Furth at that time, we secured physical points of view. the services of William D. Gude, who organized this section Most of its activities at the beginning concentrated on of the Biology Division and whose dedicated management nonmammalian work (bacteria, fungi, Drosophzla, plants, etc. ) developed it into a central information source for histology since no facilities to perform mammalian studies were availa­ work, not only for our Biology Division but also for this area ble at that time. It became most obvious that specimens more of Tennessee, thus establishing its excellent reputation. closely related to mammalian tissue would likely yield more I am most pleased to see that Mr. Gude has assembled this conclusive data to extrapolate these effects upon man. work into a detailed atlas of the laboratory mouse.