The spirit of cookery

and the flesh has become flexible or soft. While so exposed, meat breathes — that is to say, takes in oxygen of the air and gives out carbonic acid, just as if it were endowed with lungs or respiratory organs. Amongst the manifold changes engendered by this breathing or oxygenation, one is very prominent as preliminary to roasting or boiling, namely, the production or increase of a quantity of lactic acid; as this acid is not quite identical with the acid produced during I the souring of milk, it is tefmed paralactic acid, and as it I reacts upon polarized light, it is also termed optically active r lactic acid, and as derived from flesh, sarcolactic acid. This I acid does not only contribute to make the meat more tasty, j but it also helps to make it more tender, by exercising a I solvent effect upon the fibrous and tendinous parts. This I solvent action also belongs to other organic acids, e.g, , acetic , acid, or vinegar, and is at times made use of to make naturally hard and tough meat quite tender. Another important substance with which the contractile fibres of coloured flesh are soaked is the red coloicring matter myochrome; this is identical with the colouring matter of blood, or hemochrome, and, although differently arranged, has the same function, namely, that of fixing or holding oxygen, and giving it up again when it is wanted for the chemical action of the muscles. When it is heated it coagulates like white of egg, though only at a much higher temperature, and changes its colour to reddish-brown. White meat so called, e.g., the flesh of young animals, lambs, calves, and the breasts of domestic birds, contain but little of this myochrome, and great care is taken to keep this meat as white as possible, either by bleeding the animals with particular care, or by draining their bodies of all blood by long suspension. Blood is not capable of giving a savoury extract, although the blood of each species of eatable animals has a particular flavour, that of the ox and cow particularly of musk. When blood is used for cooking, e.g., in sausages called ‘ black puddings,’ the addition of several spices is necessary to overcome the alkaline flatness and absence of savour. Another ingredient of flesh is albumin, coagulable by heat, like white of egg, but differing from the latter in some properties ; it is identical with the colourless albumin of blood and lymph, and is hence termed serum-albumin. It is tasteless, and is thus only a nutritive, and not a flavouryielding, material. Next we have in muscle connective-tissue, or collagen sitbstance, which forms the sheath of the contractile fibres, binds them together in smaller and larger bundles, and supplies to most muscles not only white tendinous envelogies, so-called aponeurotic fascice, but also white and mostly attenuated tendinous attachments, or thin long outrunners called tendons. All the ligaments by which the joints are held together, and all the membranes by which bodies and organs are covered, and the latter are suspended in the bodies, consist of the collagen substance. It is called collagen because by long boiling with water it is