A VISIT TO LUTHER BURBANK. 33 5 



a stoneless plum was entirely an impossibility, something that was out- 

 side of one human lifetime; he refused to believe the statement and 

 could not be induced to risk his teeth on the experiment. To the great 

 amusement of Burbank and Osterhout, he took a knife from his pocket, 

 commenced to peel the plum and to cut away the fleshy part, in order 

 to expose the stone, which he was sure would be there. How great was 

 his astonishment when he finally did not find anything but the naked 

 eatable kernel ! 



A couple of years ago when I read in one of Burbank's price lists 

 about a stoneless plum, I shared a similar astonishment. How was it 

 possible to bring about such a great change ? Hybrids do not present, 

 as a rule, any new simple qualities, only new combinations of already 

 existing properties. The evident properties are often developed from 

 more than one factor, and such composite characters may thus appear, 

 without any new essential factors having been present. This is a 

 fundamental principle in crossing, whether it is done for scientific or 

 for practical purposes. But although the elimination of the stone is 

 only a loss and not a gain of a character, such a loss is just as much 

 outside the sphere of hybrid making. 



My astonishment was, therefore, as great as that of Bailey, and I 

 had long ago made up my mind to ask Burbank, if I ever had the oppor- 

 tunity, what secret method or what happy coincidence had enabled him 

 to effect such a fundamental change in a plant. I put my question 

 to him that evening, convinced that on the answer depended largely 

 the scientific value of our visit. And for the second time I was sur- 

 prised over the unexpected and simple reply : " About two centuries ago 

 they knew in France a ' prune sans noyau ' and I bought the fruit and 

 raised a plant in order to cross it with others of my prunes." Thus 

 there is no exception to the rule, there has been no real production of 

 a, new character, but we have only had a case of the general American 

 principle : ' try everything.' Over the whole world Burbank looks for 

 different kinds and varieties of prunes, no matter how insignificant 

 they may be, however wild and uneatable, as long as they possess only 

 one or another characteristic, which, in combination with the common 

 kinds, may bring out a new variety of greater value. 



To Professor Loeb and myself this was, to a certain degree, a dis- 

 appointment. We had expected to learn a great deal about this point, 

 the fundamental idea, if not the ultimate aim, of the studies of both 

 of us — that is, the question of the nature and origin of new characters. 

 We now surmised that Burbank's experience did not throw any light 

 on this question. 



I had before experienced a similar disappointment. About twenty 

 years ago I was occupied with experiments on hybridization for 

 horticultural purposes. I had already found at that time the general 



