Howard and Love offer three reasons why during the last four months of 1918 the deaths from influenza and pneumonia in the Army in the United States ran at a rate nearly three times as high as that among our troops in France: First, that the troops in the United States were recent recruits and therefore more susceptible to disease; second, that probably many of the troops in France who had seen much longer service had had the disease in mild form in the early spring; and, third, that the method of housing was entirely different in France. There the men were spread over a wide territory and whenever in rest area they were billeted in houses rather than crowded into barracks. Furthermore, they were living much more in the open. It was found that in commands of the Service of Supply, where troops were housed in barracks with a large number of men to a single room, the epidemic ran much the same course with high mortality, as it did in the cantonments in the United States. The percentage of infection and the fatalities from influenza and pneumonia in France were much greater among troops of the S. O. S. than among troops at the front. _Domestic cleanliness._—We have studied the relationship between influenza incidence and the cleanliness of the household by the same method used in studying overcrowding. In Table VIII we have classified according to cleanliness and according to the number of cases developing in each family. We have had four subdivisions, “very clean,” “clean,” “dirty,” and “very dirty.” There is greater opportunity for erroneous results in this table than in the one preceding because the standards of cleanliness are difficult to define. As a matter of fact we are guided entirely by the inspector’s own impression of each household, as she examined it during her visits. The following is an excerpt from the instructions given each inspector on this subject: “A few words on this subject may describe much. State of cleanliness of the individual, slovenly condition, dust and dirt, foulness of air noticed on first entering, condition of children, of kitchen sink, etc., should be noticed, and good or bad features recorded. In the poorer districts not a few families will be found in which the cleanliness, considering the surroundings, is quite laudable. Of particular importance are amount of daylight, ventilation, care of bathroom and toilet, garbage, whether windows are kept open at night.” On the basis of these returns we have classified the families as indicated, but each inspector was governed to a certain extent by the average cleanliness of her district, and it is difficult to compare the cleanest tenement with any of the districts of well-to-do individuals. We will therefore probably find it more profitable and more nearly accurate to combine the groups and classify them only as “clean” and “dirty.”