CHAP. VI.] POTATO. 143 



potato apples, or fruit. When the stalks begin 

 to wither, the tubers are ripe, and may be taken 

 up ; but most persons have not patience to watt 

 so long, and they begin to take up their early 

 potatoes before the tubers are half-grown. 



In 1845, and the three following years, a 

 dreadful disease attacked the potatoes in Great 

 Britain and Ireland, and almost entirely de- 

 stroyed the main crop. There had previously, 

 as early as 1830, been a disease among the 

 potatoes in Germany, which was called the dry 

 rot, and which made the tubers so hard that 

 they were quite unfit to use as food ; but this was 

 quite different from the murrain which made 

 its first appearance at Liege in 1842, by which 

 the tubers became soft and rotten. It was first 

 noticed in Great Britain near Hyde, in the Isle 

 of Wight, in August, 1845, and its first symp- 

 tom was a dark spot on the leaf, which spread 

 so rapidly to the stem, that in a few days the 

 whole plant became black and rotten. It has 

 been found that if the tubers are taken up as 

 soon as the stem and leaves become blackened, 

 they are fit for use ; but in a very few days 

 spots appear in them, and they rot rapidly, be- 

 coming in a very short time a mass of putres- 

 cent matter. The potatoes, as soon as they are 

 affected, acquire a pungent and nauseous taste, 

 and become totally unfit for food. Various ex- 

 periments w 7 ere tried to stop this fatal malady, 

 and the result of those conducted by Mr. 

 Thompson, in the garden of the Horticultural 

 Society of London, at Chiswick, was, that the 

 plants grown in soil manured with lime and 

 powdered charcoal, were generally very slightly 



