120 ON THE REPRODUCTION OF BUDS. 



into action ; and as nature, amidst all its exuberance, does not abound 

 in useless productions, the opinions of this illustrious physiologist are in 

 this case probably erroneous. 



Other naturalists have supposed the buds, when reproduced, to spring 

 from the plexus of vessels which constitutes the internal bark; and 

 this opinion is, I believe, much entertained by modern botanists ; it 

 nevertheless appears to be unfounded, as the facts I shall proceed to 

 state will evince. 



If the fruit-stalks of the sea-cale (Crambe maritima) be cut off near 

 the ground in the spring, the medullary substance within that part of 

 the stalk which remains attached to the root decays ; and a cup is 

 thus formed, in which water collects in the succeeding winter. The sides 

 of this cup consist of a woody substance, which in its texture and office, 

 and mode of generation, agrees perfectly with the alburnum of trees ; 

 and I conceive it to be as perfect alburnum as the white wood of the 

 oak or elm ; and from the interior part of this substance within the cup, 

 1 have frequently observed new buds to be generated in the ensuing 

 spring. It is sufficiently obvious that the buds in this case do not spring 

 from the bark ; but it is not equally evident that they might not have 

 sprung from some remains of the medulla. 



In the autumn of 1802 I discovered that the potato possessed a 

 similar power of reproducing its buds. Some plants of this species had 

 been set rather late in the preceding spring, in very dry ground, where 

 through want of moisture they vegetated very feebly ; and the portions 

 of the old roots remained sound and entire till the succeeding autumn. 

 Being then moistened by rain, many small tubers were generated on the 

 surfaces made by the knife in dividing the roots into cuttings ; and the 

 buds of these, in many instances, elongated into runners, which gave 

 existence to other tubers, some of which I had the pleasure to send 

 to you. 



I have in a former paper remarked, that the potato consists of four 

 distinct substances, the epidermis, the true skin, the bark, and its internal 

 substance, which from its mode of formation, and subsequent office, I 

 have supposed to be alburnous : there is also in the young tuber a trans- 

 parent line through the centre, which is probably its medulla. The buds 

 and runners sprang from the substance which I conceive to be the albur- 

 num of the root, and neither from the central part of it, nor from the 

 surface in contact with the bark. It must, however, be admitted, that 

 the internal substance of the potato corresponds more nearly with our 

 ideas of a medullary than of an alburnous substance, and therefore this, 



