A person who has had any infectious disease and has been thoroughly disinfected, with his clothes, may be allowed to mix freely with his fellows, in school, for instance, after the following periods. Scarlet fever: Not less than eight weeks from the appearance of the rash, provided peeling has completely ceased, and there be no sore throat. Six weeks is not enough, as there are cases of direct infection after seven weeks when all symptoms have entirely disappeared. Measles and German measles: In three weeks, provided all peeling and coughing have ceased. Smallpox and chickenpox: A fortnight after the last scab has fallen off; the hair, in case of smallpox, having been cut short and scrubbed with carbolic soap or soft soap. Mumps: Four weeks from the attack if all swelling has disappeared. Whooping-cough: Six weeks from recognition of the whoop if the cough has entirely lost its spasmodic character, or four weeks if all cough whatever has ceased. Diphtheria: In a month if convalescence be complete, there being no trace of sore throat or discharge from the nose, eyes, etc. Ringworm: When the whole scalp, carefully examined in a good light, shows no stumpy broken hairs or scaly patches. It has been very difficult to impress upon communities and individuals the extreme importance of strict obedience to the foregoing rules. There is an unfortunate tendency in too many instances for households to fail in guarding their neighbors from contact with their own members who are convalescing from disease. Even such common and simple diseases as whooping-cough, chickenpox, mumps and others that are considered especially to belong to children, frequently prove fatal to those who are susceptible to them, and it is truly wicked to permit by carelessness such an infection to reach a school or elsewhere where weaker children may suffer as a result. COMMON SENSE IN THE SICK ROOM Ventilation, Light, Temperature and Furnishings—Care of the Patient—His Temperature and Pulse—Bed Sores—The Characteristics of Fever—Simple Household Remedies—What to Put in a Remedy Cupboard—How to Keep the Baby Well To every living person air must be furnished every moment if life is to be preserved. The vital element of the air is oxygen gas, the life-giving medium, and this is diluted with nitrogen, because the oxygen itself, breathed alone, would be too stimulating for our lungs. In the delicate cells of the lungs the air we have inhaled gives up its oxygen to the blood, thus purifying it, and receives in turn carbonic acid gas and water, foul with waste matter, which the blood has absorbed during its passage through the body and which we now exhale. The blood is red when it leaves the heart, pure. It returns to the heart purple from the impurities it has picked up, and by the oxygen is once more changed to red.