INTERNAL CAUSES OF VARIATION 185 



crops. So far as is known to the writer, the same principle holds 

 in other fruits. It is the endosperm and not the receptacle that 

 is directly affected by fertilization, and any influence upon the 

 latter must be indirect and comparatively slight. 



Possible indirect effect of pollination upon the development of 

 fruit. Though the receptacle is not itself fertilized, its develop- 

 ment is conditioned upon that of its superincumbent seeds, 

 which are themselves directly dependent upon fertilization for 

 their development. 



This fleshy growth of the receptacle is, therefore, the result 

 of a kind of stimulus from the growing germ, and it is con- 

 ceivable that this stimulus may differ somewhat in degree, 

 depending upon the source of the pollen. In this way the size 

 of the fruit might be indirectly influenced by the pollen ; and 

 in fruits like the pear, which are not concentric about the seeds, 

 even the shape might be influenced in the manner noted. 



All this is quite independent of certain markings of fruit 

 which may arise by those dispositions of color which are every- 

 where responsible for stripes and spots, and whose causes are 

 not as yet understood. 



SECTION VII TELEGONY 



The term " telegony " is synonymous with " infection of the 

 germ" and the ''influence of previous impregnation." 



By this is meant the supposed influence of the male upon the 

 female in such a way as to affect future offspring by other sires. 



Breeders of animals quite generally believe that the influence 

 of one impregnation, especially the first, is permanent and will 

 affect all future offspring ; indeed, some go so far as to say 

 that a female once mated to a male of a different breed is ever 

 afterwards, for breeding purposes, herself a cross-bred animal)- 



This supposedly permanent effect of the male upon the female 

 has been especially claimed for horses, dogs, and men. 



Telegony in horses. The classic example among horses, and 

 the one that is everywhere cited as proof of the theory, is the 



1 This theory seems to be limited to animals. The writer is not aware that it 

 has ever been claimed for plants. 



