Why should indigo dyers become melancholy, and scarlet dyers choleric?[75] We do not know. But there is one thing we most certainly do know, that a poison may be disarmed by an antidote, and the amount of the latter must be in proportion to that of the former, and as epidemic and contagious diseases do most unquestionably depend upon poisons of a specific nature, and of great amount and activity, an infinitesimal remedy, however it may claim to direct and control the organic forces, under slight and ordinary disturbances, can be no more effectual in destroying the poison of fever, or small pox, than in neutralizing arsenic or prussic acid. The uncertainty which generally prevails as to the treatment of Epidemic diseases, Fevers, &c. induced me to put together the notions which are contained in these pages, in the hope of leading to some definite ideas of the causes of these affections, and consequently to a more uniform and scientific mode of treating them. I have endeavoured to shew that reproduction is a phenomenon inseparable from morbific matter, and that in all probability the vegetable kingdom is the source of the germs. {192} The train of argument adopted is such as appeared to me most natural for such an enquiry, and it rests now only with those who are capable of deciding whether such a course, though (I am sensibly aware) not without many faults in conception and execution, is calculated to advance the science of medicine and the interests of mankind. The real tree of knowledge, possesses in the spongioles of its roots, an elective property, by which truth alone can enter; nourished and sustained by this, it sends a fragrant incense and breathing odour on high, and dispels the mists of ignorance and superstition. In natural causes and reasonable deductions we must seek for instruction and solid information, for in over-straining either nature or art, deformity and error must inevitably be the result. THE END. NORMAN AND SKEEN, PRINTERS, MAIDEN LANE, COVENT GARDEN. * * * * * NOTES [1] "It matters little how vague and false hypotheses may appear at first: experiment will gradually reduce and correct them, and all that is required, is industry to elaborate the proof, and impartiality to secure it from distortion."--_Sewell_ "On the Cultivation of the Intellect." [2] It is stated by Mr. Crosse, of Norwich, that vaccination was adopted in Denmark, and made compulsory in 1800. After the year 1808 Small Pox no longer existed there, and was a thing totally unknown; whereas during the twelve years preceding the introduction of the preventive disease, 5,500 persons died of the Small Pox in Copenhagen alone.--_Dr. Watson's Lectures._ Dr. Blick, an intelligent Danish physician, corroborated the above statement to Dr. Watson himself in the year 1838. [3] Philosophy of Life, Lecture 6, translated by the Rev. A. J. W. Morrison, M.A. [4] The following I quote from Dr. Fuller on Small Pox and Measles:--