34 Mutual Independence of Hereditary Characters 



have originated separately as to time, and can also be lost 

 independently from one another. They can be combined 

 with each other in almost every proportion, every indi- 

 vidual character from complete absence through all 

 gradations being capable of attaining the highest devel- 

 opment. Frequently the conditions are so unfavorable 

 for some of them that they cannot manifest themselves 

 at all, and so remain latent. In this condition, they may 

 either persist for thousands of generations, or they may 

 appear in every generation during the development of the 

 individual from the fertilized egg, in which they are nearl) 

 all latent. 



The hereditary factors compose the entire specific 

 character ; there is no separate basis to which they are at- 

 tached. 



Although independent to the degree that each, of 

 itself, can become weaker and even disappear completely, 

 they are yet, as a rule, united into smaller and larger 

 groups. And the condition is such that, when external 

 influences, such as a stimulus to gall-formation, bring a 

 definite character into dominance, the entire group to 

 which it belongs is usually set into increased activity. 



Independence and miscibility are therefore the most 

 essential attributes of the hereditary factors of all or- 

 ganisms. 



To find a hypothesis which will make these charac- 

 teristics more comprehensible to us, is, according to my 

 opinion, the chief problem of every theory of heredity. 



