1873.] EEMARKS ON THE POTATO. 315 



sopher Mr Knight had never been heard of, and where the gardener's library 

 consisted of Abercromby, Culpepper, Down's Catalogue, and the Lichfield Trans- 

 lation of the Genera. Yet Mr Knight's crop of Ashleaved Kidneys of G95- 

 bushels and 3 pecks exceeded the rate of 25 tons to the acre. 



xVfter these statements, the most astounding part of it is that these "rule of 

 thumb " gardeners in the north of England should have obtained such a maxi- 

 mum of produce from the Potato before there were any scribbling gardeners to- 

 direct them. Though they may have read Newton's theory of gravitation, they 

 in all ^probability never applied it to the culture of the potato in the light 

 that Knight did ; but they arrived at their maximum by dint of observation 

 in their failures and successes. 



Be that as it may, I went to Downton Castle to see the Potatoes, and Mr Knight, 

 with fork in hand, took me to his Ashleaf and other kinds of Potatoes, and he 

 turned out some roots, the crop being such as would have convinced any doubter 

 that his statements in the ' Horticultural Transactions ' were correct. I gave him 

 a little of my previous experience in the culture of the Potato, which enabled me 

 to be a stanch believer in his immense crops of the then delicate Ashleaved 

 Kidney Potato. I had read Mr Knight's theory that plants, like animals, have 

 but a given time allotted to them on the earth, and I asked him what age from 

 seedlings he thought the potato began to fail. He said that at about 14 years old 

 the generality of them reached their maximum of productiveness, and after that 

 they gradually failed, till at length no one would grow them, and they became 

 extinct. 



I remarked that the Ashleaf appeared to be an exception to the ride, and he 

 said it was. 



Now I never read of this gentleman's sayings in bygone days, but the couplet 

 of Burns forces itself on my memory — 



" Thus by some hedge the generous steed deceased, 

 For half-starved snarling curs a dainty feast." 



That this philosopher's bones have been well picked there cannot be a doubt ; 

 but then the more we pick them, the more brilliant does their phosphorus 

 aj)pear. 



Hence in these observations I shall not only repeat what he, viva voce, ad- 

 vanced towards an explanation, as it afterwards proved, of the cause of the so- 

 called Potato disease, long before it absolutely showed itself, but I shall endea- 

 vour, however roughly, to utter what he would have advanced, as a means of 

 preventing such a calamitous loss of Potatoes as we now so frequently suffer, 

 had he been with us. 



It is patent to vegetable physiologists that the Potato is a plant, both stem 

 and tuber, composed chiefly of cellular tissue, its vascular tissue being but 

 trifling even in the haidm when ripe in the autumn. That this latter tissue, or 

 something approaching it, was produced in the haulm of late Potatoes more 

 than half a century ago, was clear enough, as without careful handling the men 

 got cuts on their hands when drawing the tops to make way for the plough to 

 turn out the tubers. Such was the healthy condition of these (let us call them) 

 vascular potatoes, that I have seen them stored 6 feet thick, and found perfectly 

 sound in the spring. 



The disease in question had never been heard of, but we did occasionally hear 

 of the " curl " having appeared on some favourite sorts. It would now appear 

 that the "curl" was a forerunner of the serious events which we have seen 

 befall the Potato. The " curl " appeared on the vascular kinds more generally 



