1908.] Apple "Scab" or "Black Spot." 191 



in the case of trees where the disease has been very prevalent. 



The Bordeaux mixture should be made according to the 

 following formula and id the following manner : — 



Copper sulphate ("bluestone")* 4 lb. 



Quicklime... ... ... ... ... ... 4 lb. 



Water ... ... ... ... ... ... 50 gallons. 



Dissolve the 4 lb. of copper sulphate in a wooden tub or 

 pail ; iron or tin vessels must not be used. The easiest way 

 to do this is to suspend the material, wrapped up in a piece 

 of coarse sacking, in a few gallons of cold water, from a stick 



fig. 8. — Microphotograph 01 a section of the "scab" infested twig of Cox's 

 Orange Pippin shown in Fig. 6 (A) : — {a), cells of the wood ; {b), cushion-like mass 

 of fungus-tissue, which has pushed its way out through the bark, and produced over 

 its free surface myriads of spores (c). Highly magnified. 



placed across the top of the tub or wooden pail. If this 

 is done overnight, the copper sulphate will be found to be 

 dissolved in the water by the morning. If hot water is used, 

 the copper sulphate, especially if powdered, can be dissolved 

 in a few minutes. Then add water to make 25 gallons. Now 

 take the 4 lb. of quicklime and put it in a tin pail. Add a 

 few pints of water until all the lime is slaked, taking care to 

 add only a little water at first ; in this way a thick creamy 



* In purchasing copper sulphate an article of 98 per cent, purity should be 

 demanded ; substances described as " agricultural bluestone," often adulterated 

 with iron sulphate, must be avoided. 



