We should have plenty of pure, fresh air. If children are kept in close bed-rooms, they become puny and weakly. Let them sleep where they can have abundance of pure air, in well ventilated rooms, or out of doors, in the summer time, in a safe place; it will be most beneficial for their health. 12:218. _Exercise and Mental Vigor_--Do you know that it is your privilege so to live that your minds may all the time be perfectly within your control? Study to preserve your bodies in life and health, and you will be able to control your minds. 8:135. My mind becomes tired, and perhaps some of yours do. If so, go and exercise your bodies. 6:148. In the eastern country there was a man who used to go crazy, at times, and then come to his senses again. One of his neighbors asked him what made him go crazy; he replied, "I get to thinking, and thinking, until finally I think so far that I am not always able to think back again." Can you think too much for the spirit which is put in the tabernacle? {296} You can, and this is a subject which I wish the brethren instructed upon, and the people to understand. The spirit is the intelligent part of man, and is intimately connected with the tabernacle. Let this intelligent part labor to excess, and it will eventually overcome the tabernacle, the equilibrium will be destroyed, and the whole organization deranged. Many people have deranged themselves by thinking too much. The thinking part is the immortal or invisible portion, and it is that which performs the mental labor; then the tabernacle, which is formed and organized for that express purpose, brings about or effects the result of that mental labor. Let the body work with the mind, and let them both labor fairly together, and, with but few exceptions, you will have a strong-minded, athletic individual, powerful both physically and mentally. When you find the thinking faculty perfectly active, in a healthy person, it should put the physical organization into active operation, and the result of the reflection is carried out, and the object is accomplished. In such a person you will see mental and physical health and strength combined, in their perfection. 3:247. As for health, it is far healthier to walk than to ride, and better every way for the people. 4:103. Many persons are so constituted, that if you put them in a parlor, keep a good fire for them, furnish them tea, cake, sweet meats, etc., and nurse them tenderly, soaking their feet, and putting them to bed, they will die in a short time; but throw them into snow banks, and they will live a great many years. Brother Heywood would have been in his grave long ago, if he had not led an out-door life, and {297} such is the case with others; but he is again here, and we have the privilege of seeing him. 4:295.