Professor David Ellenson writes in the New York Jewish Week:
… As a result of these texts, the Chatam Sofer contended that Jewish tradition instituted metzitzeh b’eh solely to prevent danger to the infant and stated that metzitzah b’peh was not a required part of the circumcision ceremony. In light of the rationale for this part of the ceremony, he concluded that a sponge or other instrument that could soak up the blood and safeguard the child could be employed instead. Those numerous Orthodox rabbis who have not insisted on metzitzah b’peh in the past two centuries have essentially followed his reasoning on this matter.
In light of the unparalleled prestige that the Chatam Sofer enjoys as a legal authority within the world of Orthodox Judaism, a puzzle remains as to why a number of Orthodox rabbis have dissented from his position and maintained that metzitzah b’peh is an inviolable part of the circumcision ritual.
The late Professor Jacob Katz of the Hebrew University offered a suggestion as to why this is so in a monograph he published in his Hebrew-language “Divine Law in Human Hands.”
Professor Katz reported that the Reform Rabbinical Conference held in Brunswick, Germany, in 1844, discussed the issue of circumcision and that the question of whether metzitzah b’peh was potentially damaging to the infant was addressed. During the discussion, a Rabbi Levi Herzfeld emerged as the foremost critic of this practice, and he urged that the ritual be abolished because of the danger it posed to the health of the 8-day-old boy. While the conference took no formal vote on the matter due to lack of time, other rabbis at the conference concurred with the opinion of Rabbi Herzfeld.
As a result of the criticisms these Reform rabbis lodged against a number of traditional Jewish religious practices, as well as metzitzah b’peh, seven Orthodox defenders of the tradition immediately responded in an Orthodox collection of Jewish legal opinions titled “Torat ha-Kenaot” by claiming that this Reform opposition voiced against metzitzah b’peh was motivated solely by a desire to destroy the tradition. These Orthodox spokesmen asserted that the cautions of the medical profession on this topic should be disregarded and were unyielding in their resolve that the ritual be maintained. In so doing, the ruling of the Chatam Sofer on the subject was either ignored or rejected.
Through their insistence that contemporary Jews should honor and observe this practice as a sacred part of an inviolable Oral Tradition, they transformed the ritual of metzitzah b’peh into one of boundary maintenance that separated Orthodox from Reform Judaism. For these men, the performance of metzitzah b’peh was now an obligatory part of the brit milah ceremony.