Hilgers lays stress on the wise toleration of Benedict, as expressed in these regulations of 1758, in insisting that in all cases of doubt, and particularly when the book under examination was a work of a Catholic of repute, the advantage of the doubt should be given to the author; that the author should, if within reach, be given an opportunity, before the decision concerning his book was reached, of being heard before the examiners; that the examination of any book the subject of which might not be one for general understanding should be committed to “consultors” or “qualificators,” one or more of whom must have expert knowledge of the subject-matter; that the judgment should be based upon, not the view of any one Order or group or school, but upon the whole policy of the Christian Church and with reference purely to the welfare and instruction of believers. Hilgers also commends the wise liberality of Benedict in regard to works of science. He adds: “So valuable for the influence of the people is the example of men of science, that it is not too much to say that even in the work of scientific investigation, it is their duty, irrespective of the regulations of the Church, to secure a dispensation for the reading of prohibited books or doubtful books.”[30] The Constitution of Benedict, issued under the title _Sollicita ac provida_, was considered to be so wisely framed that Leo XIII, while repealing all the earlier regulations, found it desirable to confirm and to republish this in the Index of 1900. =2. Issues of the Roman Index, 1763–1899.=--The Index of 1758 constitutes the foundation of all later issues of the Roman Index. A series of appendices were compiled at irregular intervals (from five to ten years) in such form that they could be bound in with the Benedictine Index. At longer intervals (from twenty-five to fifty years), the lists were consolidated into one alphabet and the Index, so printed, constituted a legitimate new edition. The responsibility for the compilation of these additional lists rested with the successive secretaries of the Congregation of the Index. The introduction, written by the secretary to each new appendix, follows pretty closely the wording of that of Ricchini, printed in 1758.