This section is from the book "The Complete Cook", by J. M. Sanderson. Also available from Amazon: The Complete Cook.
Good mutton is firm in the grain; of a bright red colour; the lean delicately interlarded with thin streaks of fat; the fat itself being of a brightish white, tinted with a delicate pink. The fat of rotten mutton, in which the sheep was afflicted with a liver disease, is always of a dead white, and the flesh is of a pale colour. Such mutton is both unwholesome and unsavoury. The best way to detect this kind of mutton, is to examine the liver before it is removed from the sheep. If the liver be without bladders, or other marks of disease, the mutton is sound. Ewe mutton is not so good as wether mutton; the flesh is generally paler, and the texture finer. The best mutton is that which is fed upon the natural grasses. This is the reason why the Welsh and mountain Scotch muttons are so firm, short, and sweet. The sheep have liberty to choose their own food. Mutton fed on rape and turnips does not eat so well, nor near so well, as the grass-fed. Ram mutton has a strong, and, in some seasons of the year, an exceedingly disagreeable flavour. It is said that wether mutton, to be eaten in perfection, should be five years old; but it is scarcely ever kept to that age. In wether mutton there is a knob of fat on the part of the leg, where in the ewe you will find a part of the udder.
23. Venison when young has the cleft of the haunch smooth and close, and the fat is clear, bright and thick. In old venison, the cleft is wide and tough. If, after running a long, narrow, sharp knife into the lean of venison, it comes out without smelling, the venison is sweet. Some persons like it a little gone, and others a good deal. This state of putrescency is called by gourmands haut gout, high tasted; we should rather say at once, stinking. Venison requires more keeping than any other sort of meat to make it tender, unless it be dressed immediately it is killed, that is, before it is cold.
 
Continue to: