It was inevitable when a new group of associations came to exist side by side with a large existing body of associations, from which it was continually detaching members, introducing them into its own midst with the practices of their original societies impressed upon their minds, that this new group should tend to assimilate, with the assimilation of their members, some of the elements of these existing groups.[620] This is what we find to have been in fact the case. It is possible that they made the Christian associations more secret than before. Up to a certain time there is no evidence that Christianity had any secrets. It was preached openly to the world. It guarded worship by imposing a moral bar to admission. But its rites were simple and its teaching was public. After a certain time all is changed: mysteries have arisen in the once open and easily accessible faith, and there are doctrines which must not be declared in the hearing of the uninitiated.[621] But the influence of the mysteries, and of the religious cults which were analogous to the mysteries, was not simply general; they modified in some important respects the Christian sacraments of Baptism and the Eucharist—the practice, that is, of admission to the society by a symbolical purification, and the practice of expressing membership of the society by a common meal. I will ask you to consider first Baptism, and secondly the Lord’s Supper, each in its simplest form, and then I will attempt to show how the elements which are found in the later and not in the earlier form, are elements which are found outside Christianity in the institutions of which I have spoken. 1. Baptism. In the earliest times, (1) baptism followed at once upon conversion; (2) the ritual was of the simplest kind, nor does it appear that it needed any special minister. The first point is shown by the Acts of the Apostles; the men who repented at Pentecost, those who believed when Philip preached in Samaria, the Ethiopian eunuch, Cornelius, Lydia, the jailor at Philippi, the converts at Corinth and Ephesus, were baptized as soon as they were known to recognize Jesus Christ as the Messiah.[622] The second point is also shown by the Acts. It was a baptism of water. A later, though still very early stage, with significant modifications, is seen in the “Teaching of the Apostles:”[623] (1) no special minister of baptism is specified, the vague “he that baptizeth” (ὁ βαπτίζων) seeming to exclude a limitation of it to an officer; (2) the only element that is specified is water; (3) previous instruction is implied, but there is no period of catechumenate defined; (4) a fast is enjoined before baptism. These were the simple elements of early Christian baptism. When it emerges after a period of obscurity—like a river which flows under the sand—the enormous changes of later times have already begun. (i.) The first point of change is the change of _name_.