A great deal has been written about the value of a cold bath, particularly in the morning, and many people, from a sense of duty, suffer what is almost torture taking a shower bath or a cold plunge bath on rising. When a cold bath (which should not last more than a few seconds) is followed by a good reaction, that is, when after drying, a distinct glow is felt, there is no objection to its use, and undoubtedly it has a tonic effect for those whose vitality is able to endure the shock. But cold baths for their tonic effect are desirable only when the individual is assured of their lasting benefits. Nor must one judge of the effects by the immediate results, inasmuch as the splendid feeling which follows may be succeeded by a period of depression lasting the rest of the day; in which case, the total effect of the cold bath is bad rather than good. Baths for cleanliness are everywhere desirable, and their frequency should depend upon the individual, his constitution, habits, and work; upon the season and temperature; and on the conveniences for bathing in the house. Baths for tonic effect are not necessary, and if not a pleasure, may very properly be omitted. One other point to be noted is that no practice is of more value in reducing the ravages of contagious diseases than a frequent and conscientious washing of one's hands. For germs are most certainly transmitted from one person to another, and it is accomplished more frequently by the hands than by any other part of the body. The invitation, therefore, to a guest to wash his hands before dinner is really an invitation for him to disinfect himself or to get rid of the germs which he is carrying, in order that the host and his family may not be infected during the meal. The guest owes it to his host always to accept the invitation, whether he thinks he needs it or not. Doctors recognize the necessity, and it is surprising to observe how many times during the day a doctor washes his hands, even though he may not come in contact with any particularly infectious disease. An ordinary man, on the other hand, washes his hands only when he thinks they are dirty, although his daily occupation may expose the skin of his hands to infection many times worse than that which the doctor experiences. _Mouth breathing._ Children have sometimes wondered why they were made with both mouths and noses, since they could breathe equally with either, and many years have gone by before they realized that breathing through the mouth was not intended, but that the exclusive province of the nose was to furnish air to the lungs. The reason for nose breathing rather than mouth breathing is twofold. In the first place, no provision for removing or filtering out germs from the air is made in the mouth, whereas in the nose the crooked passages, the moist surfaces, and the hairlike growths all tend to strain out any germs normally in the inspired air.