THE EFFECT OF CORTISONE ON GROWING BONE IN THE RAT.

The bodies were then thawed in 10 per cent formalin, after which the parietal bone and both tibiae were prepared free. After fixation for a maximum of 24 hr. in 10 per cent formalin, the preparations were dehydrated in absolute alcohol for 2-3 days with several changes. Most of the preparations were embedded in methyl methacrylate. The plastic blocks were sawn into slices 0-5 mm. thick, which were then ground down to a thickness of 100 /u. A number of the sections were examined by microradiography (Hulth and Olerud, 1962a). They were mounted under coverslips in fluorescence-free balsam and examined in the fluorescence microscope fitted with an UV light source (Hulth and Olerud, 1962b). Some tibia preparations from different periods of the experiment were decalcified in formic acid and sodium citrate for ordinary histological examination. They were stained with haematoxylin and eosin.