NATURAL HISTORY SOCIETY OF GLASGOW. 171 



constantly renewed. I have inquired about the wild potato, but 

 nobody knows it. Most of the people have heard that the potato 

 is a native of Chile, but think of it only as a cultivated plant, and 

 have never seen it on the hills except where planted. I find that 

 on the eastern side of the Andes, about Mendoza and San Juan, the 

 potato is scarcely known. Jose Andino was born in San Juan, and 

 lived there till he was 18. He never saw a potato till he came to 

 Copiapo. People in his native place live on maize and wheat. 

 Manual Flores was born in Mendoza, and has seen potatoes grown in 

 gardens to make salads like cucumbers. I do not know of anything 

 else to add at present. John King." 



My object in bringing this paper before the Society is a practical 

 one, to try to do something to prevent the annual recurrence of the 

 potato disease. The cultivation of the potato has of late received 

 special attention. A select committee of the House of Commons 

 investigated the subject in the summer of last year, and in autumn 

 issued a valuable report, in which it is shewn that the severity of 

 the disease has been greatly mitigated by the production of new 

 varieties, such as the Champion. Judging from the commun^ation 

 just read, it seems to me that something might be done in the same 

 direction by the introduction from Chile of sound varieties. If we 

 knew exactly the causes of the disease we might perhaps find a 

 remedy. Of course the immediate cause is a fungus, but what are 

 the remoter causes that predispose the plant to fungoid attacks? 

 We may answer this question generally by saying that by our 

 methods of cultivation we put a strain on the constitution of the 

 plant which it is unable to bear. But what is the nature of this 

 strain 1 I am inclined to attach a good deal of importance to cutting 

 the seed. By this practice we destroy the natural protection of the 

 tuber — the skin — and lessen the supply of food for the young plant. 

 We probably over-stimulate by manures, and in many cases store 

 imperfectly for the winter. Such treatment continued through a 

 course of years at last renders the plant so weak that it falls an easy 

 prey to Peronospora infestans. Now, it is noteworthy that in many 

 respects the Chilian methods differ from our own, and from all the 

 evidence before us the disease is unknown in Chile. I do not 

 think we can lay the blame on our rainy climate, for the potato has 

 failed in many different climates, and we see from the testimony of 

 Senor Julio that in the two rainy provinces of Chiloe and Valdivia the 



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