235 
to the remaining parts ; for the sap flows laterally 
as well as perpendicularly. The same reasons 
will apply to explain the increase of the size of 
fruits by diminishing the number upon a tree. 
As plants are capable of amelioration by peculiar 
methods of cultivation, and of having the natural 
term of their duration extended ; so, in conformity 
to the general law of change, they are rendered 
unhealthy by being exposed to peculiarly unfavour- 
able circumstances, and liable to premature old age 
and decay. 
The plants of warm climates transported into 
cold ones, or of cold ones transported into warm 
ones, if not absolutely destroyed by the change of 
situation, are uniformly rendered unhealthy. 
Few of the tropical plants, as is well known, 
can be raised in this country, except in hot-houses. 
The vine during the whole of our summer may be 
said to be in a feeble state with regard to health ; 
and its fruit, except in very extraordinary cases, 
always contains a superabundance of acid. The 
gigantic pine of the north, when transported into 
the equatorial climates, becomes a degenerated 
dwarf ; and a great number of instances of the 
same kind might be brought forward. 
Much has been written, and many very ingeni- 
ous remarks have been made by different philoso- 
phers, upon what have been called the habits of 
plants. Thus, in transplanting a tree, it dies or 
becomes unhealthy, unless its position with respect 
to the sun is the same as before. The seeds brought 
from warm climates germinate here much more 
early in the season than the same species brought 
