66 EXPERIMENTS MADE IN THE GARDEN OF THE SOCIETY 



deserve further trial, especially as regards plants growing in soils 

 which induce an over-luxuriance of haulm. 



Nos. 66 to 103 refer to an experiment tried August 9th, con- 

 sisting in pulling up the haulm, whicli was considerably decayed, 

 and then beating and rolling the rows. Every alternate half- 

 row was thus treated, the other half of each row being left for 

 comparison. Tlie rows ran north and south. The lialf of the 

 first row at the soutli end was rolled, the north end of the next, 

 the south end of tlie third, and so on alternately. The average 

 sound produce was somewhat less in the rolled than in the un- 

 rolled portions ; but the quantity diseased was not half' so cjreat 

 in the rolled portions as it was in the unrolled. 



The tables to Avhich these references belong will be found at 

 p. 70 and the following. 



An experiment was tried, September 2nd, of dusting the 

 foliage with sulphur. It appeared to hasten the decay of the 

 stems and foliage, and the comparative results were decidedly 

 against the sulphured portion. 



Amongst all the remedies which have been tried against the 

 disease, none appear to have been completely effectual. AVhile 

 the cause of the malady is involved in mystery, any remedial 

 application must be considered as an affair of chance. It is m ell, 

 notwithstanding, to try various remedies ; for some of the most 

 valuable discoveries have been obtained by accident. It is like- 

 wise proper to record even the failures of supposed cures, in order 

 that other trials and substances may be substituted. Various 

 theories respecting the cause of the disease have been propounded 

 and strenuously advocated, but there is still room for conjecture ; 

 and even if these should prove wrong, some of them may never- 

 theless give rise to others nearer the truth. With this view of 

 the subject, 1 may be allowed to add a few remarks. 



There is perhaps no article of food so extensively culti- 

 vated over the surface of the globe as the potato. Wheat 

 has a wide range of climate ; but the potato succeeds, or did 

 succeed, in higher latitudes than it. Co-extensive with the range 

 of the potato appears to be the influence of the disease. It has 

 occurred in all quarters of the globe. It did not commence by 

 attacking some particular variety, in a particular locality, and 

 thence progressed along with the extended cultivation of that 

 infected sort ; for the propagation of no one variety could keep 

 pace with the spread of tlie disease. Old varieties and recent 

 seedlings were, generally speaking, indiscriminately attacked ; and 

 Avhetlier tubers were brought from the native country of the potato, 

 or seeds of it from the antipodes, it was no guarantee that their 

 progeny would be sound. The contrary has been proved in both 

 cases, in the Society's garden. The universality of the disease 



