TAPPING SYSTEMS 66 



horizontal incisions is that the latex exudes from the 

 cuts and then runs down the stem, and the method is 

 chiefly employed in those cases where the latex coagulates 

 spontaneously and quickly on exposure to air. In 

 practice the incisions are usually made obliquely to the 

 axis of the stem at angles of from 45° to 60° with the 

 horizontal ; the latex runs down the channel thus formed 

 and its collection is greatly facilitated. In some cases 

 vertical incisions have been employed for tapping purposes, 

 and frequently a number of oblique incisions are con- 

 nected by a vertical channel which serves to coUect the 

 latex from all of them. 



The principal systems of tapping may be grouped under 

 the followmg heads: (1) single oblique incisions; (2) 

 V incisions ; (3) basal V or Y incisions ; (4) herring- 

 bone incisions (hah or full) ; (5) spiral incisions (half or 

 full) ; (6) horizontal incisions ; and (7) vertical incisions. 



(1) Sitigle Oblique Incisions. — In this system a number 

 of oblique incisions, varying in length according to the 

 cii'cumference of the stem, and also in the distance apart, 

 are made one above the other in a vertical row on the 

 stem. A cup to receive the latex has to be fixed at the 

 base of each cut (see fig. I, p. 67). 



Sometimes the cuts are made to overlap instead of 

 being in the same vertical line, so that the latex from 

 the top cut, having reached the lower end of the incision, 

 runs down the stem into the incision below, and so on. 

 Only a smgle cup at the base of the lowest cut is then 

 required to coUect the latex. 



(2) V Incisions. — This type of incision is made by 

 combining two oblique cuts so as to form a V. The size 

 of the V's may vary considerably, the side cuts ranging 

 from 1 to 12 in. or more in length. Usually the V's 

 are arranged in vertical rows on the stem to a height of 

 6 ft. or more, and fresh V's are subsequently made at the 

 side of the previous row. 



Cups have to be fixed at the base of each V, as in the 

 case of the single oblique cuts, but only one cup is re- 

 quired for two cuts, instead of one for each (see fig. II, 

 p. 67). 



The yield from a V cut is usually a little less than from 

 two separate oblique incisions of the same size. 



(3) Basal M or Y Incisions. — This system has been 



