EFFECTS OF EXPOSING GERM-CELLS TO RAYS OF RADIUM 237 



fluctuating variability, are transmitted from parent to offspring in 

 sexual reproduction. 



The modification of a specific group, therefore, is an expression 

 of the variation of one or more of its component individuals, and it 



Fig. 66. Omagra biennis. Permanently Arrested Development. The same Plant 

 as is shown in figure 65, six Months later. Cf. figure 65. 



is clearly conceivable that the variation of only one individual, pro- 

 vided it is of the nature known as discontinuous, and transmissible 

 by heredity, would be quite sufficient material out of which to form 

 a new specific group. 



It was from some such point of view as this that I undertook to 

 see what would result on exposure of the germ-cells, male and 

 female, of Onagra biennis to the rays of radium. I chose Otiagra 

 biennis because it was the only species available when the radium 

 could be had that had a pedigree, and of whose purity I was there- 

 fore certain. I chose the germ-cells from a belief that, if they are 

 uninfluenced by the environmental change, the resulting variation is 

 not likely to be transmitted.* 



* Blaringhem/' ^'^ however, has reported the inheritance of certain monstrosities 

 produced in Zea Mays, oat, barley, and other herbaceous plants by traumatisms, such 

 as compression, torsion, and cutting. 



