Cortical bone from the bovine femur has been studied to determine any changes in dimensions that might be caused by dehydration and subsequent rehydration of the samples. Nine control and ten emblamed axially oriented parallelepiped samples were produced with nominal dimensions of 5 × 5 × 30 mm. Sequences of oven drying and rehydration were studied, before dehydration in a vacuum desiccator prior to determining ash weights. Vacuum dehydration caused anisotropic shrinkage with statistically different (p<0.000 15) mean strains of 9200, 27 0000, and 40 200 microstrain in the axial, circumferential and radial directions respectively. The corresponding mean strains for the embalmed samples were 7100, 21 400 and 34 000 microstrain(p<0.000 15). These strains are notably greater than the typical quoted 3000 microstrain peak associated with normal physiological activities. Rehydration of either the control of emblamed samples in isotonic saline did not reproduce the original radial or circumferential dimensions. Due to the small range of ash weights from 69.8 to 75.2 per cent, no meaningful correlation between ash weight and shrinkage could be extracted from the data. These findings have a potentially dramatic impact upon the design and conduct of all in vitro studies that use bone, whether fresh or embalmed.