130 DESTRUCTIVE INSECTS OF VICTORIA : 



"In the Bordeaux district the best time is from the loth of Novem- 

 ber to the 15th of February, if the state of the soil is suitable, if it is 

 not too damp, or if a long spell of rain is expected, following after the 

 operation. 



" The following is an estimate of the cost of these two operations 

 reckoned at per hectare (2 J acres) : 



"300 francs (say 12) for the sulphur of carbon. 



tl 500 francs (say 20) for the sulpho-carbonate of potassium. 



t( I have experimented with another insecticide, of which much has 

 been said, the sulpho-carbonate of calcium, and not costing so much ; 

 but I have not used it sufficiently myself to be able to recommend it. 



" As in all circumstances and for all things, one must not be carried 

 away with enthusiasm for a certain cause, as none can be regarded as 

 perfect ; you will not get the absolute destruction of phylloxera by sub- 

 mersion, or by sulpho-carbonate of potassium, or by sulphur of carbon ; 

 the phylloxera, which each year after the respective applications, 

 whether in winter or spring, furnish the new re- invasions in June, July, 

 or August, by the hatching of winter eggs, if these winter eggs have 

 not been destroyed in time. 



"My conclusion is that two operations are necessary, absolutely 

 indispensable, to work advantageously against the phylloxera the pre- 

 ventive treatment at once, and always, and the curative treatment to 

 follow." 



The following practical instructions on the treatment 

 by sulphide of carbon are by Messieurs Marion, Conanon, 

 and Gastine (France), and which I have extracted from 

 Dr. Kirk's work : 



u 1. Doses of Sulphide of Carbon. This is a transparent liquid, with- 

 out colour, and extremely inflammable. It vapourizes rapidly, and 

 under certain conditions is explosive. It must therefore be manipulated 

 with many precautions. Besides, the odour is so strong and so charac- 

 teristic that the least quantity of vapour shows itself. 



" When sulphide of carbon is introduced into the soil it vapourizes in 

 mixing with the air contained in the particles of the soil, and these 

 vapours have enough force to penetrate far from the point where they 

 first took place, meanwhile destroying any insects which they meet. 

 Scientific experiments, the result of which have been confirmed by many 

 observers, have enabled the range of these vapours to be determined 

 according to the doses employed, the duration of their persistence in the 

 soil, and their relative insecticide-power. These data, and those con- 

 cerning the resistance of the vine itself to various doses, have regulated 

 the rules of application of sulphide of carbon to phylloxerated vines. 



" The quantities of sulphide of carbon which should be employed per 

 acre vary according to the depth and the state of permeability of the 

 soil. No account need be taken of the state of the vine, as to whether 

 it is old or young, vigorous or enfeebled, in determining the doses to be 



