In the class due to negligence may be included cases in which careless coolies place the cup upon the ground before tapping. Pieces of shavings fall into the cup, and coolies are too lazy to pick them out. More often than not coagulation in the cup is caused. As it is impossible for the European staff to supervise each individual tree tapped, some cases must continue to pass unheeded. Sometimes bark-shavings are brought in with the latex, and if a broken sieve is being used, these, with other impurities, pass into the jar, and are embedded in the coagulated rubber. This must be classified as negligence, for no manager would willingly allow the use of a broken sieve. Again, naturally coagulated lump rubber on arrival at the factory sometimes contains evident pieces of bark, leaves, and stems of leaves. For lack of supervision the average coolie would not think of picking out these obvious impurities, and would pass the whole mass into the machines. OXIDATION STREAKS.--Since the introduction of sodium bisulphite defects due to streaks, caused by portions of the coagulum becoming oxidised, have practically ceased to exist. In the usual course, and without the use of an antiseptic agent, the freshly coagulated rubber has a surface darkened by oxidation. Unless this dark surface were carefully cut off, there would result a crepe containing dark streaks caused by the mixture of the oxidised surface portion with the bulk of the paler coagulum. The presence of oxidation streaks in No. 1 crepes, now being made, would imply either that no anti-oxidant substance was in use, or that the quantity necessary to prevent this surface oxidation is exceedingly small. Although the price obtained would appear to be influenced by the presence of oxidation streaks, no evidence can be obtained that the actual quality of the rubber suffers to the same degree as does the appearance--_i.e._, there is no evidence to show that a pale rubber, in which surface oxidation has been inhibited, is intrinsically superior to one in which slight natural oxidation has been incident.