DO VAEIETIES BtJN OUT V 67 



limit of life. This idea has been widely adopted 

 and is still occasionally met with in horticultural 

 writings. Thus a writer in the Michigan Farmer, 

 for 1887, p. 3, attributes the apparent degeneration 

 of certain standard varieties of apples to the fact 

 that they originated some two hundred and fifty or 

 three hundred years ago; while other varieties, 

 such as the Baldwin which is but one hundred 

 years old, are still grown successfully for the sim- 

 ple reason that they are of later origin and are 

 supposed for this reason to have retained their origi- 

 nal vigor. Botanists have hardly accepted the idea 

 in this form, but they have generally held in recent 

 years that sexual reproduction, that is, reproduction 

 by seed, is essential to permanent vigor. It must 

 be confessed, however, that actual proof of even 

 this belief has hardly been offered. It is a belief 

 which, nevertheless, has had much influence in 

 stimulating the production of new varieties from 

 seed. The degeneration of potatoes and their 

 liability to therot has been particularly attributed 

 to their propagation from tubers instead of seed. 

 Mr. Goodrich, of New York, was mainly actuated 

 by this belief in his long continued experiments in 

 the production of new varieties of potatoes from 

 seed, particularly from the wild species, which he 

 assumed to possess greater vigor from its not 

 having been subjected to continuous reproduction 



