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BOTANICAL SOCIETY OF EDINBURGH. 



February 12, 184G. — Dr. Balfour, President, in the chair. 



Mrs. John Stewart, of Nateby Hall, Lancashire, was elected a life 

 member of the Society. 



A large collection of plants from Chippawa, Niagara, and various 

 parts of Canada, presented from Dr. Philip W. Maclagan ; and spe- 

 cimens of some of the rarer alpine plants of Scotland, presented by 

 Dr. Balfoui*, were announced. 



The following communications were read : — 



1. On the Potato Disease. By Mr. John Goodsir, Demonstrator of 

 Anatomy in the University of Edinburgh. 



In reference to the nature of the potato-disease, Mr. Goodsir stated 

 that there could be no doubt as to its general resemblance to an epi- 

 demic. Although we may not have discovered the causes of epidemic 

 diseases, we know they depend partly on local or individual circum- 

 stances which may be obviated, and which influence some epidemics 

 more than others ; and partly to general influences, commonly sup- 

 posed to be atmospheric, but regarding w^hich we actually know 

 nothing but their existence. Mr. Goodsir then alluded to the striking 

 general resemblance between the rise and progress of epidemics, and 

 the appearance, non-appearance, and increase of fungi from season to 

 season. Coupling this analogy with the opinion generally gaining 

 ground, that certain epidemics owe their existence to the growth of 

 fungi or analogous beings in the animals afflicted, Mr Goodsir con- 

 ceived that we are bound, in our attempts to explain the nature of the 

 potato-disease, not to overlook the fungi which exist in the diseased 

 tubers. After stating Mr. Berkeley's late researches into the fungoid 

 nature of the disease, Mr. Goodsir observed, that he was still inclined 

 to believe in the organic nature of the brown matter, and he founded 

 his belief chiefly on its peculiar form, and on its position in the cells. 

 This view of the nature of the potato-disease did not afford an indica- 

 tion of cure or prevention, for the diseases with the nature of vrhich 

 we are best acquainted are not always those we can most certainly 

 cure. It holds out, however, a hope that the muiTain may not recur. 

 The occurrence of fungi as the cause of disease was pointed out in 

 various instances, especially diseases of the skin, where mycodermatous 

 fungi are seen, diseases of the mucous membrane, and diseases of the 

 stomach. The occurrence of cellular plants {Torula cerevisia) during 

 fermentation, was also alluded to as corroborative of Mr. Goodsir's 

 views. (The paper was illustrated by large drawings of the diseased 

 Vol. II. 3 m 



