188 APPLICATION OF PRINCIPLES. 



without fragments of tlie amylaceous tuber adhering 

 to it. 



The provision of alimentary matter may, however, 

 be, in some cases, disadvantageous, by promoting too 

 great a development of stems and leaves, of which the 

 Potato itself is an instance. Theoretically, the more 

 nutritive matter there is for the eyes, the greater crop 

 there will be, cceteris parib-us, and so there probably is 

 of leaves and stems ; and it would seem that whole 

 potatoes should be more advantageous to plant than 

 sets. But I have proved, by a series of numerous 

 experiments, that the weight of potatoes per acre 

 is greater, under equal circumstances, from sets than 

 from whole tubers, by upwards of from seven cwt. to 

 three tons per acre ; and considerably more, on com- 

 parison of the clear produce, after deducting the 

 weight of sets employed in both cases. {Hort. Trans. 

 n. s., i. 445, and ii. 156.) In these instances, I sup- 

 posed the rankness of the vegetation from the whole 

 tubers to be the cause of the diminished crop, for the 

 stems were unable to support themselves, and were 

 blown about, laid, and broken by the wind. 



"While, however, in such plants as the Potato, all 

 the eyes were equally capable of forming new tubers, 

 it is found by experience that they do so with differ- 

 ent degrees of rapidity, according to the age of that 

 part of the stem or tuber which furnishes them. It 

 is stated by a writer in the Gardener's Magazine (vol. 

 i. p. 406), that it is well known in Lancashire to some 

 cultivators of the Potato, " that different eyes germi- 

 nate, and give their produce, or become ripe, at timea 



