86 INHERITANCE. Chap. XIII. 



believe that it is crowded with invisible characters, proper to 

 both sexes, to both the right and left side of the body, and 

 to a long line of male and female ancestors separated by 

 hundreds or even thousands of generations from the present 

 time : and these characters, like those written on paper with 

 invisible ink, lie ready to be evolved whenever the organisa- 

 tion is disturbed by certain known or unknown conditions. 



