Then the question arose, "Is the baby whose parents have consumption born with this germ in its body?" This question could not at first be answered; but tests were made by taking the children of consumptive parents away from their parents, and keeping them in homes where there were no consumptives. It was found that these babies did not develop the disease. From these and many other tests, it has been proved that consumption is not inherited, and that the reason the child of the consumptive so often has consumption is because he lives with people having the disease. [Sidenote: Evidence that consumption is a house disease] Consumption seems to be confined to certain families, and this has led many people to think that the disease is inherited, regardless of the proof that it is not. When we carefully study the facts in various cases, we find that the disease is not confined to a certain family, so much as it is to the _house_ in which the family lives. The record of a single house will illustrate how tuberculosis sticks to the house rather than to the family. From 1880 to 1901, a particular house was occupied by a father, mother, and six children, of whom four died of consumption. From 1902 to 1903 the house was occupied by another father and mother with eight children. They moved away because of the great amount of sickness in the family. At present this father and one of his children have tuberculosis. In 1904 the house was occupied by still another family, consisting likewise of a father, mother, and eight children. Now it is known that four of the children have tuberculosis, and it is feared that three others have also contracted the disease. In 1905 a son of the first occupant, with his wife and two children, returned to live in the house. The father of this family died of tuberculosis. Up to 1906 the total results from this house, scattered through four families, were as follows: five deaths, six cases in people still living, and three suspected cases. [Illustration: FIG. 66. The constant danger of infection in railway cars, where germs can live as well as in a house.] [Sidenote: Why consumption is a house disease] When the consumptive coughs, he sends fine droplets of moisture into the air. These droplets contain the germs that cause tuberculosis. The moisture evaporates and the germs are left sticking to the floors, the walls, the curtains, and the furniture of the room. When the room is swept or dusted, the germs are stirred up with the dust and people inhale them. The germ that causes consumption will live for a long time in a house; you cannot see it, but it is there. Wherever a consumptive has lived, he has left the germs of this disease behind him. [Sidenote: How to disinfect houses]