Systematic Atavism 657 



these plants, but the following year the 

 " Acme " was sown again and found true to its 

 type. Seeds saved from this generation in 1900 

 have, however, repeated the mutation, giving 

 rise to exactly the same new upright form in 

 1901. This was called by its originator " The 

 Washington." Seeds from this second muta- 

 tion were kindly sent to me by Mr. White, and 

 proved true to their type when sown in my 

 garden. 



Obviously it is to be assumed in the case of 

 the tomatoes as well as in instances from 

 other genera cited, that characters of an- 

 cestors, which are not displayed in their 

 progeny, have not been entirely lost, but are still 

 present, though in a latent condition. They 

 may resume their activity unexpectedly, and at 

 once develop all the features which they for- 

 merly had borne. 



Latency, from this point of view, must be one 

 of the most common things in Nature. All or- 

 ganisms are to be considered as internally 

 formed of a host of units, partly active and 

 partly inactive. Extremely minute and almost 

 inconceivably numerous, these units must have 

 their material representatives within the most 

 intimate parts of the cells. 



