040 / 'chicles of the Hereditary Characters. 



h) say, in the formation of the gcrni-cclls the dominant 

 and the recessive characters ma)' perhaps not separate 

 fully, leaving, either always or only exceptionally, a trace 

 of the dominant character in the germ-cell which has the 

 recessive one, and vice versa. This trace mav then be 

 latent during the course of a number of generations, until 

 at some later moment, and for some unknown reason, 

 atavistic phenomena in such hybrid races awaken the 

 memory of the original cross. Exi)erience does not as 

 yet support this view; it wants a much larger number of 

 generations before a final verdict may l3e expressed. But 

 it is obviotis that an atavism of this kind, if it occurred, 

 would suggest that the IMendelian units were of a com- 

 pound nature. 



These Mendelian factors maintain their independence 

 during vegetative life and fertilization. According to 

 previous conclusions, such crosses are always concerned 

 with elementary characters which occur in a different 

 condition in the one parent from that in which they occur 

 in the other. There are mainly four distinct conditions : 

 the active and the latent, the semi-active and the semi- 

 latent. Their vehicles do not only separate in the forma- 

 tion of the sexual cells, but occasionallv also in the vepe- 

 tative life of the plant, as is demonstrated by the occur- 

 rence of so-called bud-variations in hybrids.^ They are 

 therefore in such cases only loosely associated and not 

 blended together. 



Fluctuating variability is due to variation in the num- 

 ber of equix'alent pangenes : this explains wh\' it is onlv 

 linear fVol. I, p. 118) and why it is manifested in two 

 directions only. It goes in the plus direction bv a multi- 

 plication and in the minus direction by a diminution of 



' Sec pp. 619-620. 



