ON THE ACCUMULATION OF SAP IN ANNUAL PLANTS. 329 



different quantity, but from the different qualities of the sap in the 

 young and in the more mature plant ; for I have found the sap of very 

 young birch and sycamore trees to be specifically much lighter, and to 

 contain much less saccharine matter, than the sap of trees of greater age 

 of the same species, and growing in the same soil, and in the same 

 seasons. Under the influence of abundant light, in those climates in 

 which the melon was placed by nature, the first formed fruit probably 

 acquires a high state of perfection, possibly greater than it can ever be 

 made to acquire in less favourable climates. But this I am much dis- 

 posed to question, and to believe that, by proper management, the melon 

 may be made to acquire in the climate of England a degree of excellence 

 which it is very rarely found to possess in any climate, and that the 

 degeneracy of the finest varieties may be totally prevented. 



Very young plants of the sweet melon of Ispahan (the variety which 

 till within the present year I have chiefly cultivated) very rarely show 

 fruit ; and in my melon-house I never suffer a lateral shoot or blossom 

 of this variety to be produced at a less distance from the root than that 

 of the fourteenth or fifteenth joint above the seed-leaves : and when I am 

 anxious to obtain the fruit and seeds in the highest state of perfection, 

 I do not suffer a blossom to be produced nearer the root than its 

 eighteenth or twentieth joint. Under this mode of management, the 

 expenditure of sap, being confined to the extremity of a single stem, is 

 very small comparatively with the creation of it ; and it consequently 

 accumulates, and the fruit is therefore most abundantly nourished, I 

 conceive more abundantly than it usually is in any natural climate : and 

 its growth is always enormously rapid. 



The striped and green Hoosainee melon-plants, of which I received 

 seeds from the Horticultural Society in the last spring, being much 

 disposed to bear fruit, produced blossoms at their third joints ; but 

 being desirous of obtaining the fruit and seeds of those varieties in the 

 highest possible state of perfection, I subjected those varieties to the 

 same mode of management, and I believe with the best success, though 

 I am ignorant of the merits of those varieties under other circumstances. 



The fruit of the striped Hoosainee melon-plant requires a very long 

 period to attain maturity after it has attained its full growth, and after 

 it has apparently ceased to draw much nourishment from the plant. 

 During this period, I conceived that the plants, having all their foliage 

 in a perfectly healthy state, must be in the act of generating much more 

 sap than they were expending, and I therefore suffered two plants, from 

 which I took off the fruit in the end of August, to remain wholly 



