The Stoneless Seedling
Another of Mr. Burbank's stoneless plums. Many a visitor to Mr. Burbank's orchard has been amazed to find it possible to cut directly through a plum that exteriorly looks no different from ordinary plums. (Note the plum at the right, offering no obstacle to the knife blade.) Some visitors are skeptical and cut cautiously into the plum expecting to encounter a stone, and are chagrined when they find their suspicions unfounded.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 2 Chapter 4