As a general rule, the latter part of October, or early in November, is the time for the removal of live stock from the pastures to the shelter of the farmstead. In England and Scotland the transference is seldom delayed after these dates; but in Ireland it is no uncommon thing to see the animals grazing very much later in the year--a circumstance which the lateness and mildness of our climate account for. But whatever the date may be, the importance of such shelter is universally recognised, even by those who most neglect it and are least acquainted with the principles upon which its necessity depends. The more important of these principles have already been explained, but they may be here summarised as follows:-- 1. A certain amount of warmth is an indispensable condition for the maintenance of the life of animals. 2. The internal heat of the bodies of animals is supplied by the chemical combination which takes place between the oxygen of the atmospheric air which they inspire and certain of the constituents (carbon and hydrogen) of the food which they consume, or, to speak more accurately, of the tissues of their bodies, which are formed out of their food. It is very much in the same way in which our houses are heated by the burning of coal, turf, or wood in their fire-places, since the heat derived in the latter case is obtained from a similar source as in the former one--namely, by the union of the oxygen of the air with the carbon and hydrogen of the fuel. The only real difference between the two kinds of combustion is, that in respiration the process is conducted with an extreme degree of slowness, whilst in the ordinary fire the combinations take place rapidly, and the heat being evolved in a much shorter time is proportionately the more intense. 3. The temperature of the external parts of the animal body varies with the nature and quantity of the food supplied to it, and also depends upon the state of the weather and the character of the protection afforded to it. The colder the air, the greater will be the quantity of food required, and the more complete the shelter. In other words, a diminution of temperature, no matter how caused, will necessitate an increased amount of food and more perfect shelter, in order to maintain at the proper degree of heat the fluids of the body. It is only the external parts of the body that become cold: so long as the animal is in health its blood always maintains the same degree of temperature; but in cold weather the blood is subjected to a greater cooling power than it is in warm weather, and this cooling power it can only resist by taxing more extensively the heat-producing resources of the body. 4. Exposure to wet, even in warm weather, will tend to reduce the temperature of the body, since the conversion of water into vapor can only be effected at the expense of heat, which heat must be in great part extracted from the body of the animal itself.