In my last letter I adverted to the opinion forwarded to his Majesty's Council on the 9th of June last from the College of Physicians, in which the cholera, now so prevalent in many parts of Europe, was declared to be communicable from person to person. We saw that they admitted in that letter (see page 16 of the Parliamentary Papers on Cholera) the limited nature of the proofs upon which their opinion was formed; but I had not the reasons which I supposed I had for concluding, that because they used the words "ready to reconsider," in their communication of the 18th of same month to the Council, they intended to _reconsider_ the whole question. Indeed this seems now obvious enough, as one of the Fellows of the College who signed the Report from that body on the 9th of June (Dr. Macmichael) has published a pamphlet in support of the opinion already given, in the shape of a letter addressed to the President of the College, whose views, Dr. Macmichael tells us, _entirely coincide_ with his own; so that there is now too much reason to apprehend that in this quarter the door is closed. Contagionist as I am, in regard to those diseases where there is evidence of contagion, I find nothing in Dr. Macmichael's letter which can make an impression on those who are at all in the habit of investigating such subjects,[2] and who, dismissing such inductions as those which he seems to consider legitimate, rely solely on facts rigorously examined. He must surely be aware that most of the points which he seems to think ought to have such influence in leading the public to believe in the contagion of cholera, might equally apply to the influenza which this year prevailed in Europe, and last year in China, &c.; or to the influenza of 1803, which traversed over continents and oceans, _sometimes in the wind's eye, sometimes not_, as frequently mentioned by the late Professor Gregory of Edinburgh. Who will now stand up and try to maintain that the disease in those epidemics was propagated from person to person? Could more have been made of so bad a cause as contagion in cholera, few perhaps could have succeeded better than Dr. Macmichael, and no discourtesy shall be offered him by me, though he does sometimes loose his temper, and say, among other things not over civil, nor quite _comme il faut_, from a Fellow of the College, that all who do not agree with him as to contagion "will fully abandon all the ordinary maxims of prudence, and remain obstinately blind to the dictates of common sense!"--_fort, mais peu philosophique Monsieur le Docteur_. The time has gone by when ingenious men of the profession, like Dr. Macmichael, might argue common sense out of us; it will not even serve any purpose now that other names are so studiously introduced as _entirely coinciding_ with Dr. Macmichael; for, in these days of reform in every thing, _opinions_, will only be set down at their just value by those who pay attention to the subject.