Page:Popular Science Monthly Volume 62.djvu/286

280 in the progeny of the hybrids. The seed of each hybrid plant was kept separate and sown as a plat. In three plats from a cross between Valley (&#x2642;), a bearded variety, and Little Club (&#x2641;), there was an average of 25.7 per cent, of bearded plants. Eleven plats of the reciprocal cross averaged 25.2 per cent, beards. Six plats of a cross between Little Club and Emporium gave bearded plants to the extent of 24.6 per cent.; three plats of Lehigh $$\times$$ Red Chaff, 25.9 per cent.; and seven plats of Turkey $$\times$$ Little Club, 30.8 per cent. In the last example there were two aberrant cases, the remaining five lying between 25 and 29 per cent.

Much evidence of a similar nature has been brought forward by De Vries, Correns, Bateson and others, in addition to that given by Mendel. These investigators worked with widely different groups of plants and animals.

Thus far, no one has shown definitely that Mendel's theory is inapplicable to a single case. Correns, however, mentions hybrids which do not behave exactly as called for by theory, but I am not sufficiently familiar with the details concerning them to discuss them here. In my own work I found that the color of the chaff and the length of the head behave in a manner most easily explained by a modification of Mendel's theory. Instead of the pair of opposite characters, long heads and short heads, separating completely on the formation of pollen and ovules, they seemed to separate in all possible proportions, giving in the next generation a series of plants having heads of every possible gradation of length between those of the two parents, and even extending in both directions beyond the parents. In my work I arbitrarily separated the hybrids into three groups— long, semi-long and short heads. As this separation was entirely arbitrary, the results are very irregular, and the original figures do not represent very accurately the actual facts with reference to this character. Exactly the same thing occurred with reference to color of chaff. I have not yet had the opportunity of examining the third generation of these hybrids, so that it can not yet be stated definitely that they really form an exception to Mendel's law.

As is the case with any startling discovery, we are apt either to minimize its importance or to extend its application much beyond legitimate bounds. I fear I shall be accused of the latter. But this new thorytheory [sic] is so suggestive and offers a rational explanation to so many hitherto enigmatical phenomena, that a few suggestions as to its possible application can do no harm.