There is another long list of diseases which are contagious, that is, which one person may transmit to another. These are usually serious but their spread may be largely prevented by keeping the sick person alone, except for the necessary nurses, quarantining the house and disinfecting everything when the period of infection is past. In this class are smallpox, diphtheria, scarlet fever, measles, mumps, chicken-pox and whooping-cough. These latter are the so-called "childish diseases" which it was formerly considered impossible to escape, and little attempt was made to guard against them. Now they are recognized as serious, whooping-cough for its close relation to brain and spinal trouble; measles for their effect on the eyes and lungs; chicken-pox for its similarity to smallpox, and mumps for its general lowering of the tone of the system, allowing other diseases to gain a foothold. Special serum treatment for diphtheria and vaccination for smallpox have greatly reduced the danger from these once greatly dreaded diseases. Of preventable diseases none should receive more attention than typhoid fever, because it is a great scourge and yet it can be prevented by simple means. If we understand that typhoid is a dirt disease, that it comes only from dirt, we shall feel it a disgrace to have an epidemic of typhoid, though one of the saddest features about it is that we must suffer for the sins of others. The one who is attacked by typhoid fever may not be the one who has left dirt for the disease to breed in. Typhoid fever germs are bred chiefly in manure piles, sewers, or cess-pools, and would not be transmitted to man directly, but there are several indirect ways in which they may be carried. Flies also breed in the same places. Their legs become covered with typhoid germs, and then they fly into houses directly on the food and cooking utensils. This is one of the most common ways in which the disease is carried, and doctors tell us that the common house-fly should be known as the "typhoid fly" so that people may know the serious danger that lurks in what was formerly considered as nothing worse than an annoying foe to clean housekeeping. If houses are thoroughly screened, if cess-pools, manure piles and garbage are kept tightly covered, screened, or, still better, disinfected with chloride of lime, there will be no breeding-places left for flies and this will remove one of the greatest dangers. The other danger lies in a polluted water or milk supply. Every sewer that is carried into a stream, every manure pile that drains into a water course is a menace to health. Very frequently the farm well for watering stock is near the barn,--near the manure pile, which, as it drains, carries down millions of typhoid germs to the water-level below. The well becomes infected, the family drink from it, and soon there may be several cases of typhoid fever in the home.