To some extent, codes of ethics can be seen as reflections of enduring professional values. At the same time, they are also clearly influenced by and are the product of historical circumstances. The CMA, for instance, previously included in its Code of Ethics a strongly worded statement explicitly addressing the obligations of physicians in infectious disease outbreaks. The 1922 version reads as follows: "When pestilence prevails, it is their [physicians'] duty to face the danger, and to continue their labours for the alleviation of suffering, even at the jeopardy of their own lives" [22] . This is the only appearance in the CMA Code of this type of strong categorical language regarding the professional duty to care. Interestingly, the specific text cited above appears for the first time in the revision following the 1919 influenza pandemic and then, conspicuously, disappears from the next revision released in 1926.