The kernels of black walnuts need not be discolored if the hulls of the fresh nuts are removed as soon as the nuts are ripe.  At my farm, we have done this with an ordinary corn-sheller.  The nuts, having been hulled this way, are then soaked in water for a few hours to remove any excess coloring matter left on their shells, after which they are dried for several days out-of-doors, although not exposed to the sun since this might cause them to crack open.  Thorough drying is necessary before sacking to prevent moulding.  Kernels extracted from nuts treated this way are very light in color like English walnuts.  This enhances their market value and they command a higher price when they are to be used for culinary purposes such as cake frosting and candies where there is exposure of large pieces or halves of the nut kernel.  I find black walnuts are exceptionally delicious when used in a candy called divinity fudge.  The strong flavor of the black walnut kernel although appreciated by many people, is not as popular as that of the butternut, of which more is said in another chapter.

The food value of black walnut kernels is high since they are composed of concentrated fat and protein, similar to the English walnut, the hickory nut and the pecan.  There is also the advantage, which John Harvey Kellogg of Battle Creek, Michigan, has pointed out, that nuts are a food of high purity being entirely free from disease bacteria.  One could safely say of unshelled nuts that there is not a disease germ in a carload.

There was a time when black walnut hulls were purchased by producers of insecticides.  The black walnut hull, when dried and pulverized, produces a substance which gives body to the concentrated pyrethrum extract which is the essential ingredient of many insecticides.

One cannot leave a discussion of black walnuts without reflecting on the furniture which has been possible only through the use of vast forests of black walnut timber.  Beautiful veneers have come from the burl walnut, being formed by protuberances on the trunks of the trees near the surface of the ground.  There is a variety of black walnut which we have been experimenting with for quite a few years, called the Lamb, which has a beautifully figured grain.  As this appears only in mature timber, ours is not yet old enough to show it.

I have found that the Ohio black walnut is prone to hybridize with butternut trees in its vicinity and others have told me of its hybridizing with English walnut trees near it, which shows it to be almost as vacillating in character as our Japanese walnuts or heartnuts.  Ohio black walnuts, when planted, usually produce vigorous stocks, many of which show hybridity of some sort.  If one examines the nuts of the Ohio and finds them dwarfed or deformed, he may be sure that they have been pollinized by something other than a black walnut.  Planting such nuts, then, will grow hybrid trees.  Most of us have enough curiosity to want to try this as an experiment.