The Various Forms of Variability 



47 



what is wanted. New elementary characters arise in 

 hybridization experiments solely through this kind of 

 variability, and not as the 

 result of the crossing it- 

 self; as for example Al- 

 fred Bleu, the distinguished 

 raiser of Caladiums, has as- 

 sured me to be the case with 

 his cultures. 



3. Variability in the re- 

 stricted sense or individual 

 variability, is the name given 

 to those dissimilarities of in- 

 dividuals and organs, which 

 can be described in terms of 

 Ouetelet's laws.^ 



These laws, with which 

 Darwin was not familiar, 

 and which were only imper- 

 fectly dealt with by Wal- 

 lace^ have since that time 

 been the subject of close investigation ; with the result 

 that it has become increasingly evident that these varia- 



^ See Figs. 9-13; also Fig. 22 (curve of 40.000 beets) in chapter 

 3, § II, where also the theoretical curve is shown. 



^ Case containing- beans to demonstrate their variability in length. 

 The glass case is divided by strips of glass into nine equal partitions. 

 About 450 beans ( redspotted seeds of Phascolus vulgaris) were 

 picked from a bought sample and the individuals measured. Their 

 length varied between 8-16 millimeters, and in the following pro- 

 portions : 



Partitions . . . . i 2 3 4 5 6 7 S 9 



mm. 8 9 10 II 12 13 14 15 16 



number i 2 23 108 167 106 2>}> 7 . ^ 



The beans were then placed in the subdivisions of the jar, in such 

 a way that each compartment only contained beans of the same 

 length (measured in whole millimeters) and in the order shown 

 above. Without further treatment the beans show a grouping ac- 



Fig. 9. Glass Jar with Beans.^ 



