OF TRANSPLANTING. 283 



seasons, because of their great dampness. It will be 

 seen by reference to Mr. Thompson's tables (page 

 133), that the air is very generally in a state of satura- 

 tion in the months of October, November, December, 

 January, and February, and that it is seldom in that 

 condition at any other season. Now, although the 

 perspiration of plants is greatly diminished by the 

 removal of the leaves, it is not destroyed, for they 

 .tlso perspire through their young bark ; and there- 

 fore a saturated atmosphere, which prevents much of 

 the perspiratory action which remains from being ex- 

 ercised, is a conditio I, even when plants are leafless, 

 much too beneficial 1 o be overlooked. Nor is the ac- 

 tion upon the perspi atory power of the stem the only 

 mode in which a saturated atmosphere is important 

 at the time of transplantation ; it exercises a directly 

 favourable influence on the roots themselves. Roots, 

 at their spongioleo, or most absorbent points, are ex- 

 tremely delicate ps^rts, unprotected by a fully organis- 

 ed epidermip (22), dsstinedto exist in a moist medium, 

 and capable of being easily killed by exposure to dry- 

 ness as Will as by actual violence. The accidents to 

 which the roots of transplanted trees are liable, from 

 the ^'ery nature of the operation, are of such kind that 

 it is impossible to prevent their being exposed to the 

 air, sometimes for considerable periods of time ; it is 

 therefore obviously a point o.f the first importance, 

 that the air should be as nearly of the humidity of 

 the soil from which the roots have been extracted as 

 can be secured. How unfavourable, in this point of 

 view, the months of March, April, and May are for 



