It is true that some years ago most of the complaints were genuine in referring the cause to cotton-waste. The defect arose chiefly owing to the careless use of this material in the factory. Lumps of waste when discarded were often thrown to the ground, and became mixed with the heaps of scrap rubber and bark-shavings awaiting attention. The fault was one of sheer negligence, and nothing can be advanced in extenuation. Even when the soiled waste was thrown into the external drains, it often returned to the factory mixed up with the scraps of rubber recovered by means of the drain-screens. As far as the complaint concerns itself with cotton-waste only, the remedy is plain, and lies in the power of the management by reason of the ability to restrict the use of "waste" only to the engine-drivers and mechanics. In the vast majority of cases, however, the defect arises from circumstances beyond the direct control of the factory, and under conditions which make it difficult to check the evil. Although against instructions, and for the purpose of fulfilling other orders, some coolies persist in using pieces of cloth for cleaning cups. In course of time, unless the practice is detected, this cloth becomes coated with rubber. Careless coolies throw it away, when it may be collected by the individuals who gather earth-scrap; or it may be brought into the factory in the tappers' scrap-bag. Cases have been known in which the fibrous matter observed in the dry crepe rubber was of such a nature as to indicate that the source might be attributed to leaf-stalks which had passed through the scrap-washer. It is an easy matter to condemn the sorting as being careless, but it is another matter to instil into the mind of factory coolies such a respect for easy and sane precautions that the practice of them will be continued when the eye of the supervisor is not fixed upon the workers. It will be clear that contamination by fibrous matter should be limited practically to the lowest grades of rubber. The appearance of cotton-waste in high-grade crepes must be most unusual, and the writers have not yet seen a case in a drying-house. That it does occur, however, seems to be evident from brokers' reports. It is extremely difficult to imagine how the waste enters the rubber. One possible explanation is that a coolie may have been cleaning the rolls surreptitiously with waste, which may have passed later into the rolls together with rubber. Another explanation was offered in one factory by the observed fact that coolies engaged in cutting up coagulum, ready for passing into the machines, kept a wad of waste for the purpose of keeping the knife-blade clean. This may have found its way into the rolls. It must be recorded that in the course of many years of experience no case has been seen in any drying-house of contamination of the higher grades of crepe by fibrous matter.