xxxv.] POTATO DISEASE, I. ITS ACTIVE STATE. 277 



we shall dismiss this part of the subject briefly. Mr. 

 Berkeley, writing in vol. i. p. 9 of the Journal of the 

 Royal Horticultural Society, stated that at that time, 1846, a 

 "very serious disease" had existed for more than half a 

 century under the name of " Curl," which committed 

 " immense ravages " in the north. At the present time 

 we know that the " Curl " was, and still is caused by the 

 fungus of the potato disease, Peronospora infestans, Mont. 

 In a communication to the French Academy, 17th Nov- 

 ember, 1845, M. Boussingault wrote, on the information 

 of M. Joachim Acosta, that the malady was well known in 

 rainy years at Bogota, where the Indians live almost 

 entirely on potatoes. There was a disease of potatoes in 

 1815, and a second noticed under the name of " Dry 

 Rot " in Germany in 1 830 ; if this " Dry Rot " of potatoes 

 was equally moist with the " Dry Rot " of timber, it would 

 exactly agree with what we know of the potato disease 

 now. It must be remembered here that Fusisporium 

 Solani, Mart., often really dries up and destroys potato 

 tubers. The year 1830 was not a year of daily news- 

 papers, of sharp scientific observers, and students of the 

 microscope. It may therefore be reasonably concluded 

 that if potatoes were sufficiently diseased with " Rot " in 

 1830 to warrant a published account of the disease, they 

 most probably were diseased to a less extent for several 

 previous years, and probably before the year 1815 just 

 mentioned. Many articles appeared in the newspapers 

 and agricultural periodicals of 1833 regarding the "Rot" 

 of potatoes in the northern counties of England (see 

 Journal of the Royal Horticultural Society, vol. iii. p. 22). 

 In 1840 the disease was widely spread in Germany and 

 France, and in 1841 it again attracted great attention in 

 Belgium. A sharp observer, Dr. Morren, at that time 

 advised that the putrid stems should be immediately re- 

 moved from diseased potato plants a piece of advice which, 

 under proper conditions of the growth of the potato tuber, 

 might be followed with good results at the present day. 



