76 The Potatoe Plague. 
the meadow-grown plant will ripen far before another of the 
same species grown by a ditch side or in other moist, rich 
soil, and this last will as much exceed the meadow plant in 
size and luxuriance as the one in the meadow did the one in 
the gravel walk. The Poa annua is a species of grass which 
may frequently be found in all the three situations above 
mamed. That potatoes are not exempt from this law of 
nature I have had abundant proof. On the occasion previ- 
ously mentioned, where I planted potatoes on a piece of rich 
old turf, soaked for years with the drainage of a farm-yard, 
they never did ripen, but grew on through the whole autumn, 
and were as green and vigorous in November as they had 
been in July. At last a heavy fall of snow came, with a 
severe frost, and in forty-eight hours they were as black as 
if they had been burnt, but the tubers were still thoroughly 
unripe, and were the very worst on the table and made 
the best sets that I have ever possessed. In 1844 I had 
also a strong instance. In reclaiming an old lane some 
parts had to be lowered and some hollows to be filled up, 
and both being planted with potatoes at the same time, those 
planted where the old hollows had been, and which now had 
a considerable depth of fresh soil, grew considerably taller 
and ripened some weeks /ater than those on the ridges whence 
the soil had been taken; though even in these places consid- 
erable pains were taken to retain as much of the surface soil 
as possible; and as the ridges and depressions ran parallel to 
each other for forty or fifty yards together, the marked dif- 
ference in the time of ripening caught the eye at once. I 
have also frequently observed that potatoes planted near 
hedgerow trees (especially ash) ripen earlier than the rest of 
the field. It thus appears, as well by the analogy of other 
plants as by direct observation of the potatoe itself, that a 
deficiency of nutriment produces early maturity, and vice 
versa. Fresh soil, it will at once be admitted, contains an 
