OXIDATION OF TREE-SCRAP.--It is often noted that some scrap is dark in colour, and in this condition it is generally spoken of as "oxidised" scrap. The oxidation is probably due to an enzyme, and also to the presence of chemical substances of a phenolic nature. In the course of laboratory experiments with normal latex, it was found possible to reproduce this darkening due to oxidation by the addition of very small quantities of various phenols used in general chemical processes, and the rapidity with which the darkening was effected depended upon the quantity of the phenol added. If this rapidly oxidising latex be mixed with normal latex, it would seem that the whole bulk of the latex is affected by this tendency to rapid oxidation. It is observed that this condition under which any tree may yield rapidly oxidising latex is not a permanent one. CARE OF TREE-SCRAP.--As these scraps eventually give a grade of rubber which compares well with other and better-looking grades care should be exercised in collection and treatment so that its quality is not impaired in any way. TO PREVENT OXIDATION.--As a rule the scraps are picked over, and heavily oxidised pieces are sorted out; otherwise the crepe rubber prepared exhibits black streaks. The scraps should not be allowed to remain in the sun (which induces "tackiness"), and if they have to be kept over night they may be placed in a weak solution (1 per cent.) of sodium bisulphite to arrest oxidation. It should be recognised that such a solution will not "bleach" already darkened scrap-rubber, and the nature of its action is only anti-oxidant. BARK SHAVINGS.--In the matter of collecting bark-shavings much depends upon the organisation and nature of the labour force. Probably, on the majority of estates bark-shavings are collected systematically, but on quite a number considerable laxity in this respect has been noted. This may arise from lack of adequate supervision or from the peculiar systems of working which seem to pertain to Chinese labour. Granted that the trees are well "scrapped," and that the percentage of rubber obtained from shavings under such circumstances would be extremely small (say 2 per cent. by weight on the total output), it does not need much calculation to see that annually the loss of rubber to the estate must be considerable. It would also seem to follow that, if the adult labour declines to pick up bark-shavings carefully, it might pay to employ children for the purpose. Or, as is done in some places, the adult labour might find it advantageous to collect bark-shavings at low rates per pound.