CHAPTER XII. 



THE PRODUCTION OF NEW VARIETIES. 



CHANGE IN THE TEGETAELE WORLD — EFFECT OF CLIMATE, SOIL, AND 

 POSITION — CULTIVATION, DEGENERACY, OR DETERIORATION — DECREP- 

 ITUDE — METHODS OF PRODUCTION SELECTION VAN MONS' THEORY 



AS DISTINGUISHED FROM IT — CULTIVATED FRUITS NOT DESCENDED 

 FROM THEIR MILD TYPES — IMPORTANCE OF SECURING SEED FROM A 

 YOUNG TREE HYBRIDIZATION EXPERIMENTS OF KOLREUTER, HER- 

 BERT, KNIGHT, GAERTNER, LINDLEY, PURKINJE, MIRBEL, ADOLPHE 

 BROGNIART, CONRAD SPRENGEL, CASSINI, ALPHONSE DE CANDOLLE, 

 SCHLEIDEN, FRITSCHE, THWAITES, MR. ROGERS MANNER OF OPERA- 

 TION. 



jNE of the most interesting properties of vegeta- 

 ble, as well as animal nature, is its susceptibil- 

 ity to change. This does not extend, however, to 

 species, genera, orders, or classes, but is confined to 

 varieties; thus the seed of a pear or apple will 

 always produce the same species of fruit, while a 

 variety of these species always originates in its 

 offspring a totally different character ; and the 

 improvements of which these varieties are capable, 

 through the skill of man, are without end. Let us 

 consider some of the means which man makes use 

 of to create these changes. 



Difference of climate. It is evident that, if a va- 

 riety of peach or other fruit be brought from a 



