CULTIVATION. 



191 



poles through the flame of an open fire, or leaving them 

 in water for a few days, has also been recommended for 

 kiUing the vermin with which they are inhabited. The 

 latter plan is more effectual, hut is liable to lessen the 

 durability of the poles. 



Strebel recommends, as the best means of killing vermin, 

 that the poles should be fumigated with gaseous carbon 

 bi-sulphide, the poles — thirty or forty at a time — being 

 placed in a roomy box containing a basin filled with 

 carbon bi-sulphide. After an exposure in the closed box 



Pig. 47. — Combined pole and wire training. 



to the fumes of the liberated gas for three to four hours 

 all organisms adhering to the poles will be effectually 

 killed. About a pint of carbon bi-sulphide will be sufficient 

 to treat 1,000 poles. 



Mention may be made here of a method practised in 

 some places, with a view to economising poles, of poling 

 only every third stock, the two plants on either side being 

 trained on wire or string, as shown in Fig. 47. Although 

 this plan has the advantage of cheapness, yet it fails to 

 answer very well, because the bines grow together at the 



