To Dr. _Maclean_, however, the medical world are certainly greatly indebted, for had not his _Researches_ been published, it is more than probable that the question of Contagion would not have received the many able elucidations which the experience and science of this country has since afforded it:[182] nor would an opportunity have occurred by which the most eminent physicians, and those practically acquainted with the malady, could have delivered a _viva voce_ opinion before a Committee of the House of Commons.[183] It may be thought extraordinary that a work, so unphilosophical as that to which we allude, should have created so strong a public sensation; but when we consider the eagerness with which mankind seize any circumstance, however weak, that points towards the removal of burdens under which they are suffering, we shall cease to feel surprised that a work of such bold, and promising assertions, should have soon found its way, through commercial channels, to the table of the Privy Council; nor is it strange that government, naturally anxious to relieve commerce of unnecessary burdens, should have instituted an inquiry to ascertain whether Quarantine regulations were actually necessary, and how far they might be relaxed with safety to the country. A report was accordingly requested from the College of Physicians; who, in order to meet the wishes of the government, appointed a committee from their own body to undertake the requisite examination; it is almost unnecessary to state the conclusion at which they arrived; their report is virtually included in that of the Committee of the House of Commons (for which _see Appendix, p. 185_.) With respect to the contagious nature of those fevers which have lately committed their ravages in these dominions, especially in Ireland, the proofs appear to be so satisfactory and evident, that we question the stability of that man’s mind who can doubt, and still more who can deny it. But although the question of contagion as relating to certain epidemics appears to be firmly established, we are by no means insensible to the difficulties and anomalies with which the subject is embarrassed; several of which are so important in relation to Police legislation, that we feel it necessary to offer a few observations upon each of the following questions, and which appear to include all the leading points of controversy. I. _Are all Epidemic Fevers contagious?_ II. _Does the matter of Contagion require the aid of a certain state of the air (Pestilential constitution) to give effect to its powers, and propagation; and to what causes is the decline and cessation of a contagious pestilence to be attributed?_ III. _Can filth and animal putrefaction generate contagion?_ IV. _Can a Fever produced by fatigue, unwholesome food, &c. be rendered contagious in its career by animal filth, impure air, &c._ I. _Are all Epidemic Fevers contagious?_