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I saw experiments made by Mr. RIDLEY with the tapping 

 of trees during the afternoon ; the provisional result of 

 these experiments confirm the experience that tapping 

 during the afternoon does not pay. 



8. The cut must be made in such a way, that as 

 little bark as possible is taken away, allowing at the 

 same time for the maximum number of latex vessels to 

 be opened. As most of the latex vessels are near the 

 cambium, the cut must be made as near to it as pos- 

 sible, but so as not to injure it. The cambium is 

 the tissue from where the healing of the wound must 

 take place ; when the tapping knife touches the cambium 

 cells, they die, and consequently the healing of the 

 wound must take place after the renewal of these injured 

 cells. When the cambium dies the inner wood is exposed, 

 and there is a danger that fungus or borers may pene- 

 trate the trunk. Therefore, the cutting should be done 

 only to a determined depth in the trunk ; if it is not 

 deep enough, an insufficient quantity of latex will flow 

 out ; if on the other hand it is too deep, a wound is 

 made, which recovers very slowly and introduces an 

 element of risk with regard to parasites. We shall see 

 later on that there is an easy method of ascertaining 

 whether the tapping is done deeply enough. Again the 

 tapper must take care not to take away too much of 

 the bark. The cutting serves only to reopen the wound, 

 the quantity of the latex does not depend upon the 

 thickness of the strip of bark which is taken away. 

 The latter should be made as thin as possible and 

 as much latex will be obtained from the cut, as 

 though thicker strips were taken off the cut surface. 



