From Auguste Escoffier's Ma Cuisine (1934)

To make 5 to 6 liters of brown stock: 3 kilograms of beef shank, 2 kilograms of veal shank, a few dried pork skins blanched in boiling water for 10 minutes, 200 grams of carrots, 200 grams of onion, parsley sprigs, a bay leaf, thyme sprigs, and a small clove of garlic.