476 Mutations 



The second question whicli arose from the 

 above result was this. Could the mutation be 

 repeated? Was it to be ascribed to some latent 

 cause which might be operative more than 

 once I Was there some hidden tendency to muta- 

 tion, which, ordinarily weak, was strengthened 

 in my cultures by some unknown influence? 

 Was the observed mutation to be explained by 

 a common cause with the other cases recorded 

 by field-observations ? To answer this question 

 I had only to continue my experiment, exclud- 

 ing the mutated individuals from any inter- 

 crossing with their brethren. To this end I 

 saved tlie seeds from duly isolated groups 

 in different years and sowed them at dif- 

 ferent times. For various causes I was not 

 prepared to have large cultures from these 

 seeds, but notwithstanding this, the mutation 

 repeated itself. In one instance I obtained 

 two, in another, one peloric plant with exclusive- 

 ly many-spurred flowers. As is easily under- 

 stood, these were related as *^ nieces " to the 

 first observed mutants. They originated in 

 quite the same way, by a sudden leap, without 

 any preparation and without any intermediate 

 steps. 



Mutation is proved by this experience to be 

 of an iterative nature. It is the expression of 

 some concealed condition, or, it is generally 



