HYBRID VIGOR OR II1:TKKoSIS IG.'i 



A somewhat similar series can be arranged with animals, 

 although usuiilly in wide crosses if the hybrids can Ix' 

 obtained at all they are as large or larger than the average 

 between parents. A satisfactory interpretation of the 

 vigor of hybridization must take all these facts into con- 

 sideration, even though tliey may not be the result of the 

 operation of one single law. 



