years. Somewhat more than forty years ago one Gregor Mendel, an Austrian priest, was raising garden peas. Instead of eating them, as you and I would have done, he observed and recorded the facts of inheritance they served to illustrate. Among other things, he discovered that in the case of pairs of opposing characters possessed by the parents of any given generation, some would be inherited in such a manner that half of the offspring, while apparently possessing only the character A, would in reality have also the other one, B, in their make-up—not visible at all, but ready to appear in another generation. That is to say, we may be indeed of the Jekyll-Hyde type, only the Jekyll alone appears in us, the Hyde in some of our children or vice versa. Without going into particulars, you can easily see that if, under such circumstances, the visible or dominant character is discriminated against by selection, the race possessing that character disappears; but as Dr. Shull has recently remarked, discrimination against the recessive or hidden character is ordinarily impossible, since in two thirds of the cases it is not visible at all, but is stored away in the germ cells to appear only in the next generation. The various important economic results flowing from the Mendelian researches—which were overlooked by naturalists for forty years, have been set forth in various places, but I may call attention to the possibility that certain forms of both virtue and vice, equally discriminated against by our modern civilization, are Mendelian recessives, and that is why they continue to appear in spite of everything. We stone the prophets, but it has not occurred to us to stone also the brothers and sisters of the prophets.
A few days ago, Dr. J. C. Arthur, of Purdue University, our foremost student of plant rusts, was here in Boulder. He told me something about his researches on the parasitic fungi of the different species of sunflower. It seems that certain sunflowers, which we will call A, have rusts which appear to grow exclusively upon them; while others, which we term C, are similarly afflicted. European mycologists had found that these parasites could not be transferred from A to C, or vice versa, and so had assumed that they were different species of fungi. But Dr. Arthur made the remarkable discovery that if the rust from A was sown on the common sunflower, which we will now term B, it would grow there, and would produce spores which would grow quite successfully on C. The process could also be reversed, causing the rust of C to grow on A, after a sojurn upon the intermediate B. It is greatly to the honor of the authorities of the Indiana Experiment Station, that they have—as I believe—supported Dr. Arthur in this work of his, and appreciated its value. In some places known to me, it would be quite otherwise, and I do not doubt that some of you are wondering whether, after all, this is a mere botanical curiosity.