278 CACAO 



the spraying has been effective, &c., and therefore highly 

 valuable. In some cases where it can be, and is, properly 

 applied, there can be no possible question that spraying 

 is effective in destroying fungus spores, as I mentioned 

 at the beginning of this note ; but what is intended to be 

 conveyed is that only when it is used under the most careful 

 control can good results be regularly obtained, and that 

 badly applied it utterly fails in its object. 



It also fails unless it is continuous ; and it is highly 

 probable that if due allowance is made for probable error 

 — as is always done in careful experiments — on the ground 

 of intervening factors or unknown influences, the affirmative 

 of success so much wished for, and so often prematurely 

 recorded, may not only be considerably reduced, but in 

 many cases wholly obliterated. At any rate, it is clear 

 that no proof of success will be complete until experiments 

 have been under continuous record for a certain number of 

 seasons in succession upon the same land. 



The damage done by continuous spraying to the general 

 health of the trees does not appear as yet to have had due 

 consideration, nor has it been yet taken as worthy of 

 record. We have abundant proof that cupric sulphate 

 is destructive to vegetable matter in general ; to which 

 the reply is, that it is used in such small quantities as to 

 be an unimportant factor when its influence on the trees 

 is being considered. That it is a factor to be neglected 

 has not as yet been shown, and, as I have previously men- 

 tioned, evidence is at hand to the contrary. Records of 

 this kind should be made for comparison with the record 

 of spraying successes. 



A tree may be safely sprayed in one stage of its growth 

 with a mixture which in a younger stage would seriously 

 injure it, and it is quite certain that trees carrying open 

 flowers should never be subjected to such dressings, unless 

 some very imperative reason appears for so doing. If 

 spray can kill lichens and mosses, it can also kill the much 

 more tender flower of the cacao, and does so ; and it cannot 

 be expected to differentiate between tender growths of 



