irregularities and seeming caprices in its transmission.  It makes full allowance for other causes besides personal transmission, especially for epidemic influences.  It allows for the possibility of different modes of conveyance of the destructive principle.  It recognizes and supports the belief that a series of cases may originate from a single primitive source which affects each new patient in turn; and especially from cases of Erysipelas.  It does not undertake to discuss the theoretical aspect of the subject; that is a secondary matter of consideration.  Where facts are numerous, and unquestionable, and unequivocal in their significance, theory must follow them as it best may, keeping time with their step, and not go before them, marching to the sound of its own drum and trumpet.  Having thus narrowed its area to a limited practical platform of discussion, a matter of life and death, and not of phrases or theories, it covers every inch of it with a mass of evidence which I conceive a Committee of Husbands, who can count coincidences and draw conclusions as well as a Synod of Accoucheurs, would justly consider as affording ample reasons for an unceremonious dismissal of a practitioner (if it is conceivable that such a step could be waited for), after five or six funerals had marked the path of his daily visits, while other practitioners were not thus escorted.  To the Profession, therefore, I submit the paper in its original form, and leave it to take care of itself.

To the medical students, into whose hands this Essay may fall, some words of introduction may be appropriate, and perhaps, to a small number of them, necessary.  There are some among them who, from youth, or want of training, are easily bewildered and confused in any conflict of opinions into which their studies lead them.  They are liable to lose sight of the main question in collateral issues, and to be run away with by suggestive speculations.  They confound belief with evidence, often trusting the first because it is expressed with energy, and slighting the latter because it is calm and unimpassioned.  They are not satisfied with proof; they cannot believe a point is settled so long as everybody is not silenced.  They have not learned that error is got out of the minds that cherish it, as the taenia is removed from the body, one joint, or a few joints at a time, for the most part, rarely the whole evil at once.  They naturally have faith in their instructors, turning to them for truth, and taking what they may choose to give them; babes in knowledge, not yet able to tell the breast from the bottle, pumping away for the milk of truth at all that offers, were it nothing better than a Professor’s shrivelled forefinger.