One year certain health-principles are established, the next they are set aside for some other thing. Some articles of food are prohibited as being very injurious, but in a few months the prohibition is cast aside. One mode of diet is declared pernicious, shortening the days, and making the few that are granted undesirable. Yet, just as you are ready to accept this theory, you are told of those who have lived wellnigh to a hundred years, or perhaps have passed that period, always healthful and cheerful, yet the proscribed diet or article of food has been habitually indulged in by them. For our own part, we find it difficult to believe that the plants cultivated in our homes, and which so beautify and enliven our winters, can be injurious, provided the rooms in which they are placed are kept _well ventilated_. In severely cold weather it may not be advisable to open a window just over the plants, but when windows are raised to air adjacent rooms, where there are no flowers, then open the doors leading from them to the parlor, or winter garden, that the cold breeze from without may sweep through the whole suite of rooms for a few moments until the air is entirely changed. This, even in the coldest winter, will do the plants no harm, nor their owners either, but, on the contrary, will be very beneficial, making both more healthy and vigorous. Many a lady in mid-winter sits by the fire or register, yawning and stupidly sleepy, with a dull heavy pain over the eyes foreboding a severe headache, who could throw off all this torpidity, defy the headache, and rise up refreshed and vigorous, if she would simply throw open her doors or windows just long enough to drive out the overcharged air in the room, and by so doing bring in exchange a pure and invigorating atmosphere from the outdoor world; and house-plants will be equally benefited by the same prescription. We should not think it wise to have plants in bloom in the sleeping-apartment, unless the room was large, and the doors so arranged as to favor frequent and complete change of the air. It is always desirable, just before retiring, to raise the windows for a few moments, not only in the parlors, but in the sleeping-apartments, particularly if they have been used through the day as sewing-rooms. It will insure a more refreshing sleep, and also a brighter awakening in the morning. House-plants should be placed on a stand having castors, so that they can be easily rolled away from the windows when opened, until the room is fully aired; or, if freezing cold, an old cloth kept for the purpose, or old newspapers, should be thrown over the plants to protect them from being chilled.