It is concluded[28] that there are present in latex, on collection in the field, two types of organisms. Those which work in contact with air (aerobic) show a tendency to _prevent_ coagulation and to form an alkaline yellow slime on the surface of the latex. The others, which work in the absence of air (anaerobic), may, under favourable conditions, cause complete coagulation unaccompanied by any decomposition or offensive odour within a normal period. If air is rigidly excluded, the coagulum obtained is quite satisfactory for all purposes. [28] "Preparation and Vulcanisation of Plantation Rubber" (Eaton, Grantham, and Day), Bulletin No. 27, F.M.S. Department of Agriculture, 1918; "De la Coagulation naturelle du Latex d'Hevea Brasiliensis" (Denier and Vernet), _Comptes Rendus l'Académie des Sciences_, No. 3, July, 1917. This type of coagulation, without the employment of a chemical coagulant, and under anaerobic conditions, was the subject of a patent granted in 1914 to Messrs. Maude, Crosse and others. The process has been in use on Cicely Estate (Perak) for some years. With subsequent slight modifications the apparatus consisted in essential of a tank with a loose cover. The flanges of the cover were sufficiently long to dip into a water-seal surrounding the tank. Thus the cover may rise and fall without an inrush of air. Coagulation, in fact, can be effected thus in any kind of air-tight receptacle; and experimentally the reader can obtain a satisfactory result by filling completely with latex the bottle which has a loose stopper. Under the patent held the coagulum may be prepared either for crepe-making, or for sheets by a modification of the tank. The crepe when dry does not have the bright appearance of the ordinary "Fine Pale" standard prepared with the aid of the anti-oxidant sodium bisulphite. Unfortunately the addition of this substance to the latex in normal proportions is not possible under anaerobic conditions, as it is found to prevent coagulation, probably owing to its sterilising effect upon the anaerobic organisms. To prevent the oxidation of the rubber in actual practice, the freshly prepared crepe is soaked in a solution of sodium bisulphite before hanging to dry. The resulting colour of the rubber is quite good. It was shown by Eaton and Grantham that anaerobic coagulation is slightly uncertain in action. Owing probably to variations in the composition of the latices, or to the extent of infection by organisms, coagulation may one day be complete and on other days less satisfactory. They found further that, by the addition of small quantities of sugars, coagulation under both aerobic and anaerobic conditions was improved. The conclusion formed was that the addition of sugars created a medium favourable to the development of anaerobic organisms and unfavourable to those which cause decomposition of the natural nitrogenous constituents of latex.