No. 105.] - 379 



I have now finished the list of queries that were put forth by the 

 Agricultural Chemistry Association. In considering them, and embo- 

 dying the information hitherto obtained, I have touched upon the pirn- 

 cipal points of interest connected with the disease. 



If no advance has been made towards the discovery of the cause, it 

 is much to know what are false theories. This is of immense advan- 

 tage to the one who next takes up the subject, for he will spend no 

 time in looking over trodden ground. 



It was in this view that I thought that such a sketch of the Potato 

 Disease as I have now attempted to give, would be highly useful. 



We are forced to conclude that the origin and causes of this disease 

 are at present unknown ; its mysterious marks have appeared suddenly 

 on two continents, separated by wide oceans, under heat and drought; 

 on wet and dry, light and heavy soil, at every elevation, and in every 

 variety of potato. Those who have most carefully investigated its 

 peculiarities, most widely its range, are most undecided as to its cause. 



It is possible that Providence may withdraw this scourge with the 

 present year ; but it is also possible and probable, that it may continue. 

 Therefore should every energy be taxed, every means employed to 

 counteract and overcome a disease which, those who have most care- 

 fully studied are obliged to confess, can, by no combination of circum- 

 stances at present known, be certainly prevented. 



Edinburgh, Scotland, December, 1845. 



It was intended to have inserted the premium Essay on the Potato Disease and the 

 communication of Mr Norton immediately after the report of the Committee on roots 5 

 but it has inadvertently been placed after the flax and broom-corn report, which it 

 was designed it should precede. 



