184 Changing Plant and Animal Nature 



the breeding experiments of de Vries and of Morgan with the 

 mutations which they studied agree with hundreds of experi- 



Ituhri Lamarcki- Scintil- 



Glgas Alhida Ohlonga nervis ana Nanella Lata tans 



4 th Generation 

 1895-1896 1 



3cl Generation 

 1890-1891 



2d Generation 



1888-1889 



1st Generation 

 1886-1887 



176 S 14,000 60 



73 



Parental 

 type 



Fig. 48. Mutations in Evening Primroses 



Among thousands of evening primroses grown from seed each generation yielded 

 from a few to a hundred or more individuals that departed from the parental type 

 in some distinctive way and that reproduced the new characters consistently in 

 the offspring. Is some years five or six such mutations appeared. Some muta- 

 tions appeared repeatedly as ofifshoots of the old stock kept in cultivation. From 

 Gruenberg, Elementary Biology, published by Ginn & Company. 



ments by other workers with mutations in many species of 

 plants and animals, we are warranted in asserting that 



(i) mutations occur in all species more or less fre- 

 quently, and that 



