The fact that an angle of 45 degrees with the horizon is often adopted for the lateral cuts is largely a matter of convention. A more acute angle than 45 degrees is seldom used, but flatter cuts are adopted on a good many estates. Careful and prolonged experiments are required before any definite statement can be made as to what is the best angle under various circumstances and with different systems of tapping. A flatter cut opens the same number of latex vessels as a more acute cut extending over the same, horizontal distance, and consequently releases an equal amount of latex with the removal of less bark. On the other hand, the latex flows more freely along a steeper cut, and a smaller proportion of scrap is thus obtained. When the consistency of the latex is moderately thin, the angle of the cut can probably be reduced to one of about 30 degrees without any loss of flow and with some slight saving of bark.
Direction of Cut. In the half-herring-bone and half-spiral methods of tapping, the cuts are usually made from the right to left of the operator. There is a considerable body of evidence to show that more latex is obtained in this way than from cuts made in the reverse direction. The reason for this phenomenon is not entirely clear. It may partly be associated with the fact that tapping from right to left is easier for a right-handed person, and is therefore carried out more efficiently. But this does not seem sufficient to account for the whole of the difference.