Here you can clearly see the air bubbles in the glass elements and the cemented elements. Modern lens making has almost eliminated this defect.
Here is a great shot of all the elements. You can see the air bubbles and the worst of the fungus etching on the lower left side. It takes A LOT of damage to a lens to show in the final image. I've seen proof images of a lens that you could bare see through still create an acceptable image.
