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The potatoe is said to grow wild on the table land of New Granada, and 

 M. Acosta believes that the disease has always been familiar to the Indians. 

 It is probable, therefore, that the parasite has co-existed with the potatoe 

 in its native country. By a note to Mr. Berkeley's treatise, I learn that 

 Professor Morren considers that the fungus is of American origin. Mr. 

 Berkeley also evidently inclines to the opinion, that it is a recent intro- 

 duction. Next to South America, the disease seems to have been first 

 developed in St. Helena. In the Gardener's Chronicle, for January 22, 

 1842, and again in June 1, 1844, this disease of the potatoe, from the 

 symptoms mentioned, is evidently referred to, the rot had been experi- 

 enced in that island several years previous to 1842, causing, as was said, 

 great misery and distress to the inhabitants, potatoes being their chief arti- 

 cle of produce. St. Helena is in about the same latitude as Peru, the 

 native country of the potatoe, and nearer than any other place, in which 

 the disease has been subsequently experienced ; and when we consider 

 Low exceedingly minute and buoyant must be the seeds of this fungus, 

 when the plant itself is so small as scarcely to be visible to the naked eye, 

 is it not probable that some may have been conveyed by the wind to St. 

 Helena. Thence, it seems to have been carried to Madeira and North 

 America, and so has gradually progressed from country to country. It 

 reached England late in the fall of 1 844, and was confined chiefly to 

 Kent. There the premature decay of the foliage was observed, and a 

 large proportion of the tubers decayed. The blight was first noticed in 

 England in 1845, in the same locality where it was observed in the 

 autumn of the preceding year. Thence it travelled through England 

 and Ireland, halting mid-way in Scotland ; so that the crops in the ex- 

 treme northern parts of Scotland were free from the pest. In 1846, it 

 proceeded throughout the Highlands of Scotland, and on to the Shetland, 

 Zetland, and Feroe islands. 



In some instances the disease seems to have been communicated from 

 one place to another by means of seed-tubers. A fact which has proved 

 fatal to many theories, and which seems to indicate that the chief cause 

 of the disease did not previously exist in these places, but that it was in- 

 herent in the seed-tubers. At Bermuda, Oporto, the Cape of Good 

 Hope, and in Poland, the crops which were observed to be first or exclu- 

 sively attacked were those raised from seed-tubers obtained from America 

 or England. Mr. Berkeley has observed young plants of the fungus 

 springing from within the cells of a potatoe. The germs of these could 



