Rabbi Nehemia Halevi Ginsburg (1788-1852) was the son of a disciple of the founder of Chabad Hassidism, Rabbi Shneur Zalman of Liadi (ca. 1745-1812). He married the daughter of Zalman Welkes of Dubrovno (today in Belarus), also a Chabad hassid. After Nehemia’s wife met an untimely death, the widower married Gitta Rochel, daughter of Rabbi Hayim Avraham, who was the son of the aforementioned Shneur Zalman of Liadi. Thus Nehemia was embedded in the early Chabad Hassidic community.Nehemia’s livelihood came from a tallit-producing factory that he inherited from his first father-in-law. In addition to his successful business, Nehemia was also a man of learning, though he did not serve in an official rabbinic capacity. He never published his Torah writings, but his correspondence was published posthumously in three volumes under the title Divrei Nehemia (Vilna 1866; Vilna 1869; Warsaw 1887). These volumes show Nehemia communicating with leading authorities, in particular those associated with Chabad Hassidism.The third volume preserves an exchange with Rabbi Menachem Mendel Schneersohn of Lubavitch (1789-1866), commonly known as the Tzemah Tzedek – the title of his scholarly writings in Jewish law.Nehemia discusses a particularly pertinent issue: “Regarding the fast of the approaching Tisha Be’av, out of concern for the cholera diseases, may the Merciful One save us.” The correspondence is undated, so it is difficult to place it in historical context. This may be a reference to the second cholera pandemic which hit Russia in the years 1830-1831. The outbreak in Russia triggered Cholera Riots as a response to quarantine measures taken by the czarist government. This pandemic is regarded as the event that gave rise to the notion of global health. Recollections of local restrictions from this pandemic and the fallout from the outbreaks are widely recorded in Jewish sources.Alternatively, the correspondence could be from the third cholera pandemic which reached Russia in the years 1847-1851. This pandemic is famous for the research conducted by Dr John Snow (1813-1858). Snow documented clusters of the outbreak in London, and identified germ-contaminated water as the source of cholera, rather than miasma – noxious air. Snow succeeded in petitioning the removal of the water pump handle in Bond Street, thereby curtailing the spread of the disease. Alas, the broader implication of Snow’s findings would be accepted only years later.RETURNING TO the correspondence: The first letter in the exchange has not been preserved. We pick up the discussion with Nehemia’s learned response to the Tzemah Tzedek regarding the possibility of being lenient on the Tisha Be’av fast, even when the health risk of fasting is unclear. The end of Nehemia’s response is missing. From the surviving text and from the continuation of the exchange, we can surmise that Nehemia felt that under the dangerous circumstances of the pandemic, even healthy people should not fast on Tisha Be’av, lest the fast weaken the person and make him susceptible to the disease.Printed immediately after Nehemia’s response, we have the Tzemah Tzedek’s second letter (which was also included in his own collection of responsa), and Nehemia’s second letter – both undated.The Tzemah Tzedek opened his second letter acknowledging that Nehemia’s analysis was sound. Nonetheless, in locales where the pandemic is not so harsh, it would be better to eat the minimum amount rather than gorge on food, in order not to erase the fast day from the Jewish calendar. It would appear that the Tzemah Tzedek was also concerned with the spiritual fallout of any decision. Perhaps wanting to add a guiding principle, the Tzemah Tzedek reminded Nehemia that the Merciful One desires the heart. As for places where the pandemic was not raging and a person chose to fast, the Tzemah Tzedek added further instructions: “To advise him and to warn him not to leave the door of his house the entire day. And when he goes out, to force him to have, over his nose and mouth, a small piece of komper and a bit of mint grass.”The word “komper” is written with Yiddish orthography and at first blush it is not clear what the Tzemah Tzedek was referencing. Perhaps the final letter had been dropped off and the suggestion was to walk in public with a compress over the nose and mouth. If this is the case, then we have a precedent for the current requirement to wear masks!However, it would appear that this is an incorrect reading. It is far more likely that the Yiddish word is referring to camphor – a plant favored by homeopaths to this day.In his Magnacopia, William Bateman (1787-1835) made numerous references to camphor as an ingredient in various compounds for medicinal purposes. The extended title of the work gives more details of its nature: “A library of useful and profitable information for the chemist and druggist, surgeon-dentist, oilman, and licensed victualler.” The title page of the volume describes the author as a “practical chemist, and late chemist in ordinary to George IV, and the Royal Family, London and Brighton.” Bateman’s volume was first published posthumously in 1836, and was quickly reprinted in expanded editions (second edition, 1837; third edition, 1839). Each edition included more medicinal uses for camphor. Bateman, however, did not suggest using camphor for the prevention of cholera.In 1866 – the year the Tzemah Tzedek died – Dr. Joseph Kidd (1824-1918) published a booklet in London titled Directions for the Homeopathic Treatment of Cholera. Page 2 of the booklet lists the ingredients required and the list begins with “Strong Tincture of Camphor.” Further in the work the author repeatedly returns to the homeopathic value of the plant: “When diarrhoea sets in suddenly... camphor is the best remedy” (p. 3). And a few pages later: “In case of the coming on of cholera symptoms... the best thing to be done, until a medical man arrives, is to give camphor...” (p. 6).The addition of the mint grass – following miasma theory – is suggesting that a person who goes outside should have mint on hand in order to avoid the ill effects of “night air” wafting into the body.Thus the Tzemah Tzedek does not provide us with a precedent for wearing a face and nose mask. He was referring to a medicinal recommendation. The specifics of his health counsel are based on miasma, a theory that has been debunked in favor of the germ theory of disease.The exchange is nonetheless significant because both Nehemia Halevi Ginsburg of Dubrovno and Rabbi Menahem Mendel Schneersohn recognized the need to be lenient with regard to fasting during a pandemic. The Tzemah Tzedek rightly raised the issue: How do we preserve the soul of the tradition in times when we are forced to cancel time-honored practices? The writer is on the faculty of Pardes Institute of Jewish Studies and is a rabbi in Tzur Hadassah.