The author has succeeded in still further simplifying the process by the preparation of what he would propose to call "fat sugar." Having noticed that the addition of, say, 10 per cent. of powdered cacao to sugar forms an almost ideal powder for immediate compression in the tablet machine, the idea occurred to him to reproduce, as nearly as possible, the physical condition of cacao by covering each particle of powdered starch with a thin layer of fat, which can readily be done by triturating starch with liquid petrolatum. While other fat, such as cacao butter, "Crisco" or paraffin, might be used for this purpose, by dissolving the fat in ether and thus distributing it over the starch, permitting the ether subsequently to evaporate, the author has found that liquid petrolatum, 1 part, distributed over 3 parts of starch forms a powder which added to sugar in proportion of about twenty per cent. renders it admirably suitable for compression in a tablet machine. The starch might be sweetened by previously triturating it with an alcoholic solution of saccharin and permitting the alcohol to evaporate; though this sweetening is not essential. For starch, thus prepared, the author proposes the name "fat starch", the formula for which will be found in Chapter VIII. Sugars containing twenty per cent. of "fat starch", are ready for immediate compression in the tablet machine; and admit of admixture of a moderate amount of medicament without losing this quality. If a large amount of medicament is to be incorporated, then an additional amount of "fat starch" should be allowed. Sugars containing "fat starch" the author has called "fat sugars" for want of a better name. He is aware of the fact that petrolatum is not a fat in the true sense of the word. Nevertheless it is, no doubt, its "fatty" nature that does the work; other fatty substances, such as cacao butter or "Crisco", producing the same result as far as rendering the powder suitable for compression in the tablet machine is concerned. Liquid petrolatum has the advantage over these of being devoid of tendency to rancidity. Excessive trituration interferes with the efficiency of the fat starch, evidently by distributing the fat all over the powder, rendering it homogeneous, which is inimical to tablet making. Therefore in case of the red fat sugar which is used as a vehicle for poisonous medicaments that require very thorough trituration, it is recommended that the fat starch be added after the trituration. The author would suggest that the pharmacist prepare the various fat sugars described in Chapter VIII and that he keep them on hand, in a cool and _dark_ place, adding the medicament as prescribed by the physician, making use of Chapter VII for guidance in the elaboration of individual formulae. CHAPTER V. THE TABLET MACHINE.