Page:Popular Science Monthly Volume 67.djvu/351

Rh this goes on every year; fourteen or fifteen such bonfires a year are not uncommon. One consisting of 10,000 to 15,000 roses, luxuriantly flowering seedlings, annihilated the work of a number of years after the selection of only three good varieties. Half a million lily bulbs were entirely destroyed after fifty of the best had been separated for further cultivation. And so I could cite a number of instances.

It is evident that the chance of finding something good is much greater if the selection can be made from hundreds of thousands instead of from a few hundred only. Those who wish to compete with Burbank will have to accept this principle, and if this can not be done, they had better follow a different method and select species that admit the use of different methods.

It is theoretically of great interest to compare Burbank's principle with the methods of selecting generally in vogue in Europe. There the work is not performed on such a large scale. Preference is given to repeated selections, and the idea is prevalent that the desired results can be reached only by following the regular road. The question is whether by such repeated selection we proceed faster than by a single sowing on a larger scale. "We can easily calculate the proportion, and it can be said that with five years' work a hundred times smaller number of plants have to be cultivated. This would, of course, lessen the expenses in proportion, but there is always the disadvantage of the result being available so much later.

When novelties are wanted in varieties of Begonias, Geraniums, Dahlias or Fuchsias, for instance, which annually produce many new forms, the hastening process would be of no value, but in new genera unexpected results are often attained, and in that case the hastening method will amply repay the expense. Yet these questions are the secrets of breeders. Of scientific importance is the question whether repeated selections are alone sufficient to bring about the same end, and further if by this means more variations are produced.

We have no facts which would decide this, and I would not have brought up the question, had it not been for its great influence on the study of evolution. It is closely connected with the question whether species slowly merge into one another or whether they originate by mutations. In the former case small deviations would increase in the course of generations, and thus a long series of intermediate forms would connect the new and the old species. In the latter case a jump is made without any intermediate stages. So long as there were not sufficient instances of this mode of change, and so long as we had to rely upon cultivated varieties only as proof, the first proposition was naturally the most probable. It rested on experience in agriculture and horticulture in regard to improvements of races, and it was believed that species in nature originated in the same manner. The