Frankfurt a. M. in Germany seems to have been the first to provide a specialized observation cottage for uncertain cases among children. This was established in 1900 and is much used by the juvenile court. Although it has a separate building and an isolated division of the grounds it is, however, connected with the local hospital for the insane. An improvement in this respect was made with the first provincial school for psychopathic children under compulsory training established near Leipzig at Kleinmeusdorf. This serves also as a distribution station and has two observation divisions through which all _fürsorge_ children in the province pass. Only the psychopathic cases remain indefinitely. Detention homes for juvenile delinquents in this country quite generally are used for temporary quarters for cases to be observed, although these are not isolated from the other children. If an entirely separate observation institution is not possible, a more definitely recognized probationary period for observation of the uncertain cases should be arranged within other institutions. The efforts for clearing-houses for mental defectives such as that in New York City and the Ohio Bureau of Juvenile Research will help to distribute individuals to their proper institutions. The ideal is a separate observation home where all cases in which the question of mental deficiency and mental disease is raised may be sent before the individual is labeled. The effect of commitment to an institution for the feeble-minded, insane, or delinquent can be guarded against much better if the observation home is entirely isolated from all other institutions. The separate institution, however, is more difficult to obtain than a separate division or cottage in an existing institution. The latter forms a valuable intermediate step and is better than merely giving uncertain cases additional attention when other duties permit. As a matter of legal procedure, diagnosis raises the troublesome question of expert advice in court. Two decisions have to be made about each case. First, is the individual deficient enough to justify isolation or guardianship? Second, considering the means of care available in the particular community, how should the deficient be cared for? The first is primarily a question which requires expert knowledge in mental development and should be so handled. The second decision requires knowledge about the individual's home and about the facilities for guardianship or isolation. It should be left with the authorities thus informed. This will usually be the court unless there is a commissioner or a committee especially charged with this duty.