Eastman 910, by the Kodak Corporation. It wasn't developed specifically for that purpose, but it was found useful for a lot of things once it became available. It was originally developed in the late 40's, but not used for it's original purpose, assembling bombsights... See Wikipedia.
I used a number of things for the cracked skin. Bag Balm, and Udderly Smooth, among other things. If the cracks are really bad, super glue will seal them, and then you can apply nearly anything to soften the skin and keep if from cracking further, or doing serious bleeding.