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XXIX. — On the Potato Disease, hy H. Cox. 
Prizi: Essay. 
The lamentable failure of the potato crop in 1845 bas given rise 
to many theories as to its cause ; some imagining that it was a 
fungus ; the seeds of which, being borne about in the air, were 
deposited on the leaves, and thence carried down with the sap 
into the tubers ; while others contend that it was caused by 
atmospheric influence : for my own part^ I am strongly of opinion 
that the latter supposition Is most correct. The potato was not 
the only vegetable affected, — the ash, the oak, the poplar, the 
hazel, the vine, the apple, pear, and plum, but more particularly 
the walnut, the French bean, mangold wurzel, carrots, and 
turnips, suffered alike. We have a walnut-tree here remarkable 
generally for the firmness of its fruit; yet last year, out of nearly 
2 bushels of its fruit, there was not one nut with the least symptom 
of a healthy kernel, the leaves exhibiting the same appearance as 
those of the potato, and that about the same time ; and this tree 
was no more than a fair sample of all the walnut-trees in oui 
neighbourhood. My scarlet-runner beans ceased to grow after 
the beginning of August. All the early varieties of turnips in 
the garden began to deciy at the top ; a splendid piece of Dale's 
hybrid turnips was nearly destroyed ; our swedes Avere affected 
almost in the same degree as the potatoes; the mangold wurzel, 
particularly the orange globe, was affected at the rate of one in 
five ; and carrots at the rate of one in eight ; even the cabbage 
as beginning to decay when the dry weather in the third week 
in August set in. 
I will now proceed to set down some facts relative to the potato 
disease, in the hope that, though they certainly do not solve the 
mystery, they may throw some light, however faint, on its cause 
and its remedy. As to what kind of potato was most injured, I 
think we can say nothing positive ; yet certainly those varieties 
that were fast approaching to maturity before the ungenial 
weather set in, were but little if at all affected. I dug a bed ot 
the early ash-leaf kidney the fust week in August; a portion of 
them lay on the ground several weeks, but not the slightest 
symptom of disease has appeared on them up to the present 
moment, although for experiment sake I covered some of them 
with another variety that was entirely rotten : another bed, only 
4 feet distant, j)lanted from the same heap, but several weeks 
later in the season, was growing vigorously in July, and probably 
would not have been ripe until the beginning of September: 
these were taken up in the third week of August and laid in 
the sun ; out of 6 pecks of these I could not find half a peck 
sound at the end of the wee k : the same remark will applv to 
