I was taught that, but the wording was "I baptize thee..." That same CAtholic encyclopedia gives that wording as the current one. They add:
>In English, the term christen is familiarly used for baptize. As, however, the former word signifies only the effect of baptism, that is, to make one a Christian, but not the manner and the act, moralists hold that "I christen" could probably not be substituted validly for "I baptize" in conferring the sacrament.
and
In case of necessity, baptism can be administered lawfully and validly by any person whatsoever who observes the essential conditions, whether this person be a Catholic layman or any other man or woman, heretic or schismatic, infidel or Jew [sic. A lot of the language dates to the original encyclopedia of 1917.].
The essential conditions are that the person pour water upon the one to be baptized, at the same time pronouncing the words: "I baptize thee in the name of the Father and of the Son and of the Holy Ghost." Moreover, he must thereby intend really to baptize the person, or technically, he must intend to perform what the Church performs when administering this sacrament.