OF THE ALBURNOUS VESSELS OF TREES. 133 



Every gardener knows that early varieties of the potato never afford 

 either blossom or seeds ; and I attributed this peculiarity to privation of 

 nutriment, owing to the tubers being formed preternaturally early, and 

 thence drawing off that portion of the true sap which, in the ordinary 

 course of nature, is employed in the formation and nutrition of blossoms 

 and seeds. 



I therefore planted, in the last spring, some cuttings of a very early 

 variety of the potato, which had never been known to blossom, in garden 

 pots, having heaped the mould as high as I could above the level of the 

 pot, and planted the portion of the root nearly at the top of it. When 

 the plants had grown a few inches high, they were secured to strong 

 sticks, which had been fixed erect in the pots for that purpose, and the 

 mould was then washed away from the base of their stems by a strong 

 current of water. 



Each plant was now suspended in air, and had no communication with 

 the soil in the pots, except by its fibrous roots, and .as these are perfectly 

 distinct organs from the runners which generate and feed the tuberous 

 roots, I could readily prevent the formation of them. Efforts were soon 

 made by every plant to generate runners, and tuberous roots ; but these 

 were destroyed as soon as they became perceptible. An increased lux- 

 uriance of growth now became visible in every plant, numerous blossoms 

 were emitted, and every blossom afforded fruit. 



Conceiving, however, that a small portion only of the true sap would 

 be expended in the production of blossoms and seeds, I was anxious to 

 discover what use nature would make of that which remained ; and I 

 therefore took effectual means to prevent the formation of tubers on any 

 part of the plants, except the extremities of the lateral branches, those 

 being the points most distant from the earth, in which the tubers are 

 naturally deposited. After an ineffectual struggle of a few weeks, the 

 plants became perfectly obedient to my wishes, and formed their tubers 

 precisely in the places I had assigned them. Many of the joints of the 

 plants during the experiment became enlarged and turgid ; and I am 

 much inclined to believe, that if I had totally prevented the formation of 

 regular tubers, these joints would have acquired an organization capable 

 of retaining life, and of affording plants in the succeeding spring. 



I had another variety of the potato, which grew with great luxuriance, 

 and afforded many lateral branches ; and just at that period, when I had 

 ascertained the first commencing formation of the tubers beneath the 

 soil, I nearly detached many of these lateral branches from the principal 

 stems, letting them remain suspended by such a portion only of alburnous 



