512 EFFECTS OP ANNUAL EESTING. 



artificial season of growth, is over, in order to prepare them for 

 the duty of a succeeding season; although this operation is 

 performed in summer, its effect is to expose them to dryness, 

 which arrests their growth, and favours the deposit in their 

 wood of the matter required for the produce of a succeeding 

 year. 



The effects of a very dry atmosphere are necessarily an 

 inspissated state of the sap of the plant, and this in all cases 

 leads to the formation of blossom-huds and of fruit. It thus 

 operated upon some Pine-apple plants in Mr. Knight's garden, 

 to such an extent as to cause even the suckers from their roots 

 to rise from the soil with an embryo Pine-apple upon the head 

 of each, and every plant to show fruit, in a very short time, 

 whatever were its state and age. Very low temperature, under 

 the influence of much light, by retarding and diminishing the 

 expenditure of sap in the growth of plants, comparatively with 

 its creation, produces nearly simUar effects, and causes an early 

 appearance of fruit. 



The operations of forcing are essentially influenced by these 

 facts ; and, by a skUful alteration of the periods of rest, we are 

 enabled to break in upon the natural habits of, plants, and to 

 invert them so completely that the flowers and fruits of summer 

 are obtained to load our tables even in winter. Of this, the 

 following instance, taken from a paper by Mr. Knight in the 

 Horticultural Transactions (vi. 232), is a sufficient illustration. 



" A Verdelho Vine, growing in a pot, was placed in the 

 stove early in the spring of 1823, where its wood became per- 

 fectly mature in August. It was then taken from the stove and 

 placed under a north wall, where it remained till the end of 

 November, when it was replaced in the stove, and it ripened its 

 fruit early in the following spring. In May it was again 

 transferred to a north wall, where it remained in a quiescent 

 state till the end of August. It then vegetated strongly, and 

 showed abundant blossom, which, upon being transferred to the 

 stove, set very freely, and the fruit, having been subjected to 

 the influence of very high temperature, ripened early in the 

 month of February." 



The Strawberries of February and March are in like manner 



