“These modifying conditions do not disturb the true theory of the escutcheon. _Other things being equal, the escutcheon is indicative of the quantity and quality of milk._ Many are misled in estimating the value of the escutcheon, because they have not the patience or the capacity to observe the varying conditions. The escutcheon is of immense practical value. It is easily seen the conditions of flesh do not change it, and animals of all ages, above three months, may be examined by it, and their milking qualities determined with a good degree of accuracy. Other things being equal, the animal with the better escutcheon will invariably make the butter maker. During nearly thirty years of observation, the writer never observed a first class cow that had a poor escutcheon. The escutcheon must be of great value to those who are breeding, and endeavouring to improve thorough-bred cattle of the various milking breeds. It offers a test that may be applied before milking age, and it may be applied to males as well as females. _Though the pedigree is ever so long, and though it contains many good ancestors, the animal should be rejected from the breeding herd, unless it has a good escutcheon._” “One of the Farmers,” a regular correspondent of the _American Agriculturist_, writes in the number for November, 1878: “THE VALUE OF THE GUENON MILK MIRROR.—Taken with a good udder and milk-veins, good digestive functions, and capacity for food, good health and thrift, the Guenon milk mirror is a valuable indication of both the quantity and duration of the flow of milk. This seems to be demonstrated by the experience of thousands who have given the subject careful study, and I have never yet met the man who ridiculed it, and called it “folly,” who was able intelligently even to outline the prominent types. The number of calves which do well or ill as milkers, very nearly as indicated by their milk mirrors, is so large, that one of the principal practical uses to which a knowledge of the Guenon system can be applied is in selecting calves to raise, and, of course, to those who buy cows, it comes equally well in use.”