One can compare a milch cow to a fruit tree, which gives more fruit this year than the next. When the sap of the tree carries vigor to the development of the fruit, the growth of the wood remains nearly stationary. When, on the contrary, the tree gives but little fruit, the sap turns to the profit of the wood, to give, after a repose of several years, a greater quantity of fruit, and to continue thus by alternative successions. It is the same with the cow, for it is seldom that her produce keeps the same during three consecutive years, for the reason that, when the nourishment absorbed by her turns to the profit of the milk, the milk is more abundant; when, on the contrary, the nourishment goes to fat, the milk diminishes. The variations in the milk quantity should be justly attributed to the influence of atmospheric circumstances of the seasons, which react on the quality of hay and fodder in augmenting or diminishing the nutritive juices of the food. Cows which are fed in good pastures surpass the product which I have assigned to their class and their order, while those which are in poor and wet pastures have necessarily inferior produce, unless the latter have in the stable nourishing food, more abundant and more succulent than they are able to get for themselves out of doors. If, for example, the well-fed cows, or those grazing on rich pasture lands, should give as much as twenty to twenty-five quarts of milk per day; these same cows, taken and fed on poor pasture, will give only about ten or twelve quarts. If, on the contrary, one takes the cows raised on a poor soil, transfers them to rich pastures, the milk produce of these same cows will be superior to that they gave in their original lands. My readers should well understand that in the valuations of my classifications that I have not pretended to assign a rigorous and absolute amount. I have been only able to give an approximate figure to each class and to each order, adopting the medium limit of the ordinary amount of the different breeds of various localities. The atmosphere, the care, and the different foods of each country, all these different things exercise upon the animal, an influence favorable or unfavorable, according to the nature of the soil. There are many other circumstances which should be considered, and which would disturb the harmony of the figures of my valuation and the normal quantity. Such are, for example, the case of sickness, accidents, &c. That is the reason I have adopted, in determining the quantity of cows of each order, a medium figure, such as is shown in the classification. I will also observe, relative to those animals to which I assign approximate weight in the course of this work, that, following the customs of commerce, of sale, and of butchers, this weight is dead weight, the animal being deprived of the skin, intestines, head, feet, &c.