Abstract: In the Biology Division, the maintenance of animals containing radioactive materials posed many problems. In addition to routine care of the animals, protection had to be provided for the personnel who worked with the contaminated animals. Frequent air changed in the room in which the animals were caged were necessary: farm workers were required to wear masks; animal cages were checked regularly for radiation; acid was used on the sawdust in the excrete pens; and a new, more efficient type of cage was designed. The most import feature of the new cage was that the support for the screen floor was outside the confines of the cage. Stainless steel was the preferred metal for case construction. Photographs and working drawings of cages for mice, rats, guinea pigs, rabbits, and goats, and several types of metabolism cases are included in this paper. Cage decontamination was accomplished with the aid of complexing agents such as citric acid or sodium tartrate. Under certain conditions, nitric acid was used.

Abstract: Although we are generally interested in nuclear resonance levels, our measurements on Mn55 (naturally occurring Mn is 100 percent Mn55) were undertaken in order to corroborate Goldhaber's discovery of an extremely large scattering by this element.