Dear of troy: We used the same paraffin you use for sealing jelly jars, it was dissolved in chloroform to enable it to penetrate the tissues. Incidentally, though hazardous, the waste mixture of chloroform and paraffin made a very powerful paint remover for refinishing old furniture.
The name "paraffin" was given because there are no unsaturated carbon atoms to permit ready chemical reaction, and the chain is very long, making it a solid at room temperature. Which reminds me, some anal orifice in Army who knew nothing about the process, sent us to tropics with paraffin with melting point so low it was very soft in Manila. I had to hold an ice-cube to surface of tissue block just before cranking the microtome. Made my work a lot harder. I was lucky that I had Servel type refrigerator to make ice cubes. Reminds me, I used to see bombers overhead doing nothing but circling high up, to make ice for officer's mess at Air Force Messes. That was expensive ice.