A VISIT TO LUTHER BURBANK. 341 



list very little good is obtained, and then only by accident. This occurs 

 very seldom in Burbank's cultures. 



When he wishes to experiment with wild flowers Burbank goes out 

 himself in search of specimens. He carefully compares the different 

 places of growth and investigates the variation in individuals. Many 

 days are thus employed in gathering together one kind in order to find 

 out existing dissimilarities or to see whether they promise anything for 

 future cultivation. Such specimens are then transferred to his ex- 

 perimental grounds, and when established are subjected to crossing. 



With crossing or hybridization we usually understand the sexual 

 union of two individuals belonging to different species or varieties. In 

 practical plant breeding, however, it is not sufficient to combine two 

 types, but three, four, and even five or six kinds are thus united, so as 

 to bring out as many desirable qualities as possible in one single variety. 

 It is, of course, impossible to predict what result will be obtained, and 

 it must be left to chance and the future to decide what combinations 

 are the most desirable. Often crossings are made only with the object 

 in view that among all the combinations something good may turn up. 

 In this case the breeder wants to destroy the equilibrium of existing 

 characters, to make the constant forms unstable, and then to select the 

 best out of the many balancing properties. When the parents them- 

 selves are variable their offspring will naturally be more so, and the 

 number of differences increases with the number of hybrids experi- 

 mented upon. 



There is also a chance that latent or sleeping characters may be 

 brought to light. From a scientific point of view we know, as yet, 

 nothing about this, but Burbank holds the opinion that in many cases 

 one character prevents another from becoming visible. For instance, 

 in crossing, the first one meets an opponent which has kept it back — as 

 is often the case in the crossing of varieties — and this latent character 

 gets an opportunity of becoming active. We can naturally not detect 

 what dormant qualities are hidden in a plant, and may, therefore, expect 

 all kinds of surprises. The combinations may be desirable, and the 

 hybrids can be propagated immediately, or they may be the reverse and 

 need further crossing before the unfavorable traits are eliminated. 

 Unknown atavistic properties may in this way become evident and may 

 play an important part in the development of future generations. 



In other cases the crossings are made with a certain purpose in 

 view. These are the instances from which we learn the most, and 

 which at the same time give the best chances for quick and favorable, 

 results. A certain number is selected of species or varieties, which 

 together contain those characters we want combined in one type; 

 the undesirable properties we try to eliminate. As the crossings 

 result in all kinds of combinations, it is necessary to produce them in 



