THE MUTATION THEORY. 



181 



in the appearance of anomalies or mutations; but only a change of 

 external conditions which can introduce such influences as may be 

 favourable for their production. 



There are several other very interesting experiments one would 

 like to refer to, as fasciation and torsion, &c., but the above will 

 show that there is an immense amount of valuable matter in the volume. 



