The Book of Household Management by Mrs. Beeton

100. OSMAZOME is soluble even when cold, and is that part of the meat

which gives flavour and perfume to the stock. The flesh of old animals contains more _osmazome_ than that of young ones. Brown meats contain more than white, and the former make the stock more fragrant. By roasting meat, the osmazome appears to acquire higher properties; so, by putting the remains of roast meats into your stock-pot, you obtain a better flavour.