Discrimination between Heavy Water and Water by the Mouse

Abstract

THE experiment described here indicates that mice arc able to discriminate between D₂O and H₂O. Two male litter mates of Mus musculus domesticus (strain T–O) were kept in separate Harwell type cages, each fitted with two water bottles. In the experimental cage, one bottle contained D₂O and the other glass-distilled H₂O, and in the control cage each bottle contained glass-distilled H₂O. The bottles were refilled every 24 h and the quantity taken from each during the previous day was determined. The bottles were replaced in the cages in a random manner, following Fisher and Yates's table of random numbers. The experiment was continued for 14 days and Table 1 shows the quantities of liquid taken during that period by the two mice.