Cacao shell has a high nitrogenous content, and if burned yields about 67 lbs. of potassium carbonate per ton. In the Annual Report of the Experimental Farms in Canada, (1898, p. 151 and 1899, p. 851,) accounts are given of the use of cacao shell as a manure. The results given are encouraging, and experiments were made at Bournville. At first these were only moderately successful, because the shell is extremely stable and decomposes in the ground very slowly indeed. Then the head gardener tried hastening the decomposition by placing the shell in a heap, soaking with water and turning several times before use. In this way the shell was converted into a decomposing mass before being applied to the ground, and gave excellent results both as a manure and as a lightener of heavy soils. On the Continent the small amount of cacao butter which the shell contains is extracted from it by volatile solvents. The "shell butter" so obtained is very inferior to ordinary cacao butter, and as usually put on the market, has an unpleasant taste, and an odour which reminds one faintly of an old tobacco-pipe. In this unrefined condition it is obviously unsuitable for edible purposes. Shell contains about one per cent. of _theobromine_ (dimethylxanthine). This is a very valuable chemical substance (see remarks in chapter on Food Value of Cocoa and Chocolate), and the extraction of theobromine from shell is already practised on a large scale, and promises to be a profitable industry. Ordinary commercial samples of shell contain from 1.2 to 1.4 per cent. of theobromine. Those interested should study the very ingenious process of Messrs. Grousseau and Vicongne (Patent No. 120,178). Many other uses of cacao shell have been made and suggested; thus it has been used for the production of a good coffee substitute, and also, during the shortage of sawdust, as a packing material, but its most important use at the present time is as cattle food, and its most important abuse as an adulterant of cocoa. The value of cacao shell as cattle food has been known for a long time, and is indicated in the following analysis by Smetham (in the Journal of the Lancashire Agricultural Society, 1914). ANALYSIS OF CACAO SHELL. Water 9.30 Fat 3.83 Mineral Matter 8.20 Albuminoids 18.81 Fibre 13.85 Digestible Carbohydrates 46.01 ------ 100.00 ------ From these figures Smetham calculates the food units as 102, so that it is evident that cacao shell occupies a good position when compared with other fodders: FOOD UNITS. Linseed cake 133 Oatmeal 117 Bran 109 English wheat 106 _Cacao shells_ 102 Maize (new crop) 99 Meadow hay 68 Rice husks 43 Wheat straw 41 Mangels 12