Roasting in a closed oven, or _baking_, consists in exposing substances to be roasted to the action of heat in a confined space, or closed oven, which does not permit the free access of air, to cause the vapour arising from the roasted substance to escape as fast as it is formed, and this circumstance materially alters the flavour of roasted animal substances. _Roasters_ and ovens of the common construction are apt to give the meat a disagreeable flavour, arising from the empyreumatic oil, which is formed by the decomposition of the fat, exposed to the bottom of the oven. This inconvenience has been completely remedied in two ways, by providing against the evil of allowing the fat to burn; and secondly, by carrying out of the oven by a strong current of heated air, the empyreumatic vapours, as fast as they are formed. Such are the different processes of roasting meat. _Rationale._--The first effect of the fire is to rarify the watery juices within its influence which make their escape in the form of steam. The albuminous portion then coagulates in the same manner as the white of an egg does, the gelatine and the osmazome[21] become detached from the fibrine, and unite with a portion of the fat, which also is liquified by the expansive property of heat. The union of these form a compound fluid not to be found in the meat previously. This is retained in the interstices of the fibres where it is formed by the brown frothy crust, but flows abundantly from every pore when a cut is made into the meat with a knife. In consequence of the dissipation of the watery juices, the fibrous portion becomes gradually corrugated, and, if not attentively watched, its texture is destroyed, and it becomes rigid. Chemists prove that the peculiar odour and taste of roasted meat depends on the development of the principle which has been called _osmazome_, or the _animal extractive matter_ of the old chemist, a substance which differs very much from every other constituent part of animal matter _chemically_, in being soluble in alcohol--and to the _senses_, in being extremely savoury or sapid. It is upon this principle, which seems to admit of considerable varieties, that the peculiar grateful flavour of animal food, (whether in the form of broth or roasted,) and of each of its kinds, depends. Osmazome exists in the largest quantity in the fibrous organs, or combined with fibrine in the muscles, while the tendons and other gelatinous organs appear to be destitute of it. The flesh of game, and old animals, contains it in greater quantity than that of young animals abounding in gelatine. [21] Derived from οσμη, _smell_, and ζωμος, _broth_.