390 
On the Potato Disease. 
ill the other case an unsound one. From this many persons may 
conclude that they have only to provide a store of unsound sets in 
Older to secure a good sound crop next j'ear. But let me warn 
such persons, at least, not to place their sole dependence on such 
a rotten foundation, for I can assure them, from actual experience, 
(although success may have attended the practice this season, on 
account of the soil and weather being in a favourable state for 
])romoting vegetr.lion during the former part of the season,) that 
had the soil been harsh, and the weather cold and wet subse- 
quently, the shoots would have been attacked with gangrene soon 
after they were formed, and the greater part of them would have 
perished. In 1841 I lost nearly an acre in this manner, the sets 
having been cut from tubers obtained at Tooley-street, diseased 
in precisely the same way as at the present time ; while of the 
crop adjoining, from sound sets, I lost scarcely a plant. 
It may ap2:)car to some persons that, because the present season 
has not been precisely the same as the last, the cause of the dis- 
ease cannot be referred to tlie atmosphere. Yet so iniiversal has 
ihe calamity been, that it seems to me almost impossible that it 
could be produced by anything else — for, what other subtle medium 
pervades the whole globe? What, short of those extremes which 
destroy plants entirely, is more injurious to their health than 
sudden and violent transitions? And have we not had these? 
Yes; and in so unusual a degree in both years, that every man 
who notices such occurrences at all, would, independently of their 
disastrous consequences, long remember the years 1845-6. Until 
these changes ensued, the crops in the open ground looked sound 
and healthy throughout the country. I do not notice tliose grown 
in open borders through the winter, as they are clearly exposed to 
too many vicissitudes, however skilfully managed ; nor need I 
more than barely ret'er to a few diseased crops, which may have 
been produced in neglected or badly managetl pits — while in ad- 
joining gardens I have known plants in perfect health, owing to 
the superior skill of the gardener in protecting them from atmos- 
pheric injuries. Of such men, there are many who know that in 
an unsuitable atmosphere the organs of plants cannot perform 
their proper functions, and that, as soon as these cease, the plants 
themselves become the prey of gangrenous ulcers, parasitic fungi, 
and noxious insects. But in an inquiry of this kind we must look 
chiefly to the efli'cts upon the general crop; and this, I repeat, 
appeared in perfect health until those changes took place, to which 
J have before referred ; but soon after, every plant, young or old, 
became affected. Subsequently, liowever, the weather here be- 
came more moderate, and many plants which 1 have seen grow- 
ing out of doors from this year's tubers, as well as one or two 
plants which I have since grown in my greenhouse, were apjia- 
