commonly understood—that is, consisting of the husband, wife, children, and immediate dependents like relatives and servants—but it comprehends all persons living alone where they maintain their own establishments, and all larger aggregations of people subject to one common supervision, such as the inmates of hotels, hospitals, prisons, asylums, etc. So in nearly all Federal and State censuses in this country and all censuses abroad the family has comprehended hotels, boarding-houses, lodging-houses, penal and reformatory institutions, and every aggregation of individuals living under one roof, or has related in some way, either arbitrarily or otherwise, to one head. The inmates of a great hotel, or a great college, or a prison constitute, for census purposes, a family. It would seem at first thought that this artificial extension of the composition of the family would have a disturbing influence upon the average size of the family, but a careful analysis of results indicates that such influence is very slight. In the census of Massachusetts for 1885, the census family in its average size consisted of 4·58 persons. The Massachusetts State census offered facilities for ascertaining just the effect of considering institutions and other bodies as families upon the normal family. Eliminating all families coming under the artificial designation, it was found that the average size of the actual normal family of Massachusetts in 1885 was 4·45. The influence, therefore, arising from the inclusion of the artificial or arbitrary family, so far as that State taken as a whole was concerned, was but ·13 per cent—that is, the difference between 4·58, the average for all families of all sizes, and 4·45, the average of the normal family alone. Practically, it makes but little difference, then, so far as great bodies of people are concerned as, for instance, the population of a State—whether the families are considered on the basis of the actual normal family or on the ordinary census basis, which includes all aggregations living under one roof or having certain relations to one head. It would not do, however, to consider this as a rule in small aggregations of people. As an illustration, Danvers, in the State of Massachusetts, contains a large asylum for the insane. The number of families in 1885, including the asylum, was 1,474, representing a population of 7,061. The average size of families on this census basis for the town of Danvers in the year named was 4·79; but, eliminating the asylum as a family, the average size of the families was 4·17, too large a variation for accurate calculations. Again, in the town of Concord, in the State named, containing the reformatory prison, the average size of the family, including the reformatory, was 5·15; excluding it, it was 4·62. Taking a college town, Wellesley, the average size of the normal family was 5·10; but, including Wellesley College, it was 6·15, or an