Duration of Races of Plants. 167 



to act as a medium of communication between the earth and 

 the extremities above. This is proven from the fact that the 

 pecuharities of growth with other characteristics of varieties, 

 remain unchanged in their habits, on these new sorts. The 

 vigor of a feeble growing eort, is not materially effected to 

 promote its growth, if any, by being grafted on a vigorous 

 stock. If it were otherwise, we should have nothing to de- 

 pend on as landmarks to guide to satisfactory conclusions, 

 except the fruit, as to what the variety is. It is, therefore, 

 fallacious to look to this source for the permanent continuance 

 of a variety in health or existence ; but each sort must wholly 

 depend for duration on its own constitution, and this will dif- 

 fer very widely in different sorts. 



That many valuable fruits once perfectly and generally 

 healthy, and free from blemish, are no more so, will hardly 

 be disputed, among which may be named, in our own country, 

 the White Doyenne Pear, once the pride and boast of that deli- 

 cious family of fruit, and the Pennock Apple, once an universal 

 favorite. This has become so generally affected in the west, 

 with spots or flakes of dry decay throughout the flesh, that 

 it is rare to meet with a perfect specimen. This disease is 

 not identical with the bitter rot, but very distinct, having none 

 of the bitter taste predominant in that disease. Many other 

 parallel cases might be named, but they are not deemed im- 

 portant to establish the fact that varieties may, and do, wear 

 or run out. 



Is there, then, not a want of candor, after science has pro- 

 duced an illegitimate offspring with a defective constitution, 

 to throw itself back on the lata governing the original race, 

 and argue, from that law, that there can be no such thing as 

 a sort running out "? 



The above reflections were induced by the reading of an 

 article from The London Gardener'' s Chronicle, and repub- 

 lished in the New England Parmer, by Prof. Lindley, in 

 which the writer in fact admits the position contended for, 

 but most strenuously endeavors to avoid the conclusion, and 

 treats those who differ with him, with a degree of asperity 

 unbecoming one occupying, in the scientific world, the exalted 

 position he does. They are not offered as advancing new or 



