VARIATION IX PEDIGREE-CULTURES 213 



In Mr. Burbank's cross of the English walnut (Juglans regia) -with the 

 California walnut (Juglans Californica) the first generation shows a certain 

 blending of the traits of one species with those of the other. In the next 

 generation appears every conceivable kind of variation in every feature of the 

 plant and in every function of its organs. 



The last sentence offers a fair example of the misrepresentation to 

 which Mr. Burbank's horticultural work has been so profusely the 

 object. A similar progeny of a hybrid oak is included in experimental 

 cultures in Xew York, and the observer may readily see that the physi- 

 ological possibilities are not exhausted in either case. To illustrate 

 the possible variations in form would require many millions of indi- 

 viduals, as may be seen when a simple computation shows that seven 

 single differentiations would require more than sixteen thousand indi- 

 viduals for their exemplification, if the characters behaved as indivisible 

 units. If, however, qualities or characters are capable of modification 

 or variation, as indicated by the quotation, the number of different 

 forms of any organ of the entire plant would be so large as to make 

 estimates useless. Then again by what extended experimentation have 

 the conceivable variations in every function been ascertained? 



A wider range of literary license prevails in some recent articles by 

 Mr. E. A. Ortmann. Among other inaccuracies he says: 



De Vries failed entirely to take notice of this fundamental principle (inter- 

 gradation), and to show that his elementary species and his mutations are 

 not connected by intermediate forms. 



Although somewhat familiar with ' Die Mutationstheorie ' and 

 ' Species and Varieties,' no explanation occurs to me to account for 

 this mistaken statement. A few combination forms were found and 

 faithfully recorded by de Tries, but these were certainly not inter- 

 grades, whatever might be said of them. 



Mr. Ortmann's discussions introduce a novel feature, in his estimate 

 of the futility of experimental methods, which has the sole merit of 

 boldness, coming at a time when the greater number of workers in the 

 subject are turning from discussions and statements of opinion to 

 actual observations. A mistrust is shown by him of experiments 

 ' under artificial and unnatural conditions, as for instance in the 

 botanical garden, or with domesticated forms.' Several months ago 

 the following characterization of this attitude was given in a paper on 

 the subject : 2 



Popular belief in the influence of environment and the inheritance of 

 acquired characters finds its commonest expression in ' that plants have been 

 changed by cultivation.' Domesticated races are spoken of as 'garden forms' 

 by botanists and horticulturists, with the implication that they are specialized 

 types resulting from the effects of tillage. Now so far as actual cultivation 

 is concerned, this assumption is without foundation, since at the present time 



2 ' Heredity and Origin of Species,' Monist, January. 190G. 



