Certain diseases, epilepsy and meningitis, are undoubtedly causes of feeble-mindedness. The evidence, however, seems to be that they are so rare compared with the mass of mental deficiency that after 5 years they may well be offset by the excessive death rate among the feeble-minded. That recoveries from feeble-mindedness are insignificant is generally agreed. Among the 20,000 in institutions in 1910 only 55 were returned to the custody of themselves. This is further evidence of the fundamental, if not congenital, nature of the deficiency. While the evidence submitted above makes it seem fair to assume that the increase in the frequency of a certain degree of intellectual deficiency with age is probably negligible, it is not clear that the decrease with age in the proportion of feeble-minded caused by an excessive death rate may be neglected even for the test ages 5 to 25. By searching the literature it has been possible to assemble the records for nearly 3500 deaths among the feeble-minded in institutions in this country and Great Britain distributed by ages in ten-year periods. This evidence is presented in Table I. The number of cases under five years of age living in the institutions is so small that the deaths under five years are certainly misleading. They have, therefore, been omitted from the table and the distribution calculated for those five years or over (_123_, _154_, _204_, _205_). Comparison is made with a similar distribution of the total deaths for a period of five years from 1901 to 1904, inclusive, within the area of the United States in which deaths are registered, compiled from the special mortality report of the Bureau of the Census (_206_). This registration area has a population of about 32,000,000. The general agreement of the distribution of deaths among the four different groups of institutional inmates seems to make it reasonable to assume that the United States group of institutional deaths for the year 1910 is a conservative description of excessive death frequency at the early ages among the feeble-minded in institutions. TABLE I. _Age Distribution of Deaths in the General Population and Among Feeble-Minded in Institutions._