My design, in entering upon the following little work, has been to collect, and to compress within as narrow a compass as possible, the principal facts and evidences upon which the claims of Vaccination are founded; that the public may be furnished, in a concise but comprehensive form, with the information which is essential to their forming a correct judgment on this momentous question.

That much misapprehension and some prejudice prevail on this subject, my recent observation and experience have convinced me; and when I reflect on the pernicious effects, which, in Newcastle and its neighbourhood, are at this time taking place in consequence of them, and which they must continue to produce while they are permitted to exist, I feel that a collective detail of the evidence calculated to remove them is much needed, and that, being sensible of this, it becomes a duty incumbent upon myself to endeavour to supply so important a desideratum.

In making this attempt, I have been desirous of avoiding any unnecessary delay, and have therefore, perhaps, been obliged to collect facts, and to deduce arguments from them, with a degree of haste, which, while it must have occasioned many imperfections in the execution of my design, will, I trust, be admitted as some apology for such defects: I am willing, however, to hope that they will not be found of sufficient magnitude materially to interfere with the useful tendency of the estimate.

The works of those writers whom I have consulted, and whose authority I have quoted in support of the efficacy of Vaccination, are familiar to the Medical Profession, and, with scarcely an exception I believe, its members have drawn the same satisfactory conclusion from the facts which are detailed in them. But as these works, are, for the most part, strictly professional, they have not come before the public in general, who have not, in consequence, had equal opportunities of convincing themselves of the true value of Vaccination. It is, however, manifestly more important, in proportion as their relative number is greater, that the latter should be convinced of this, than the former only. The present estimate, therefore, is more particularly intended to satisfy the doubts, and to remove the apprehensions of the community at large; though I trust, should I in any degree have succeeded in the attempt, it may also be read by my professional brethren not without some portion of satisfaction and of approbation.

But, after all, should my object in endeavouring to convince the more enlightened parts of the community, (from whom alone I can hope for a proper consideration of the evidence I have adduced,) be attained, much will yet remain to be done: and I have endeavoured to point out the necessity of a general co-operation, in order to give the fullest effect to the paramount capabilities of Vaccination.—Amongst the poorest and least informed classes of society, a written evidence of this description, can scarcely be expected either to gain access or to meet with the requisite consideration; and the ignorance, the prejudices, and the apathy, which have been found to exist in some of them, must therefore be overcome by other means. It is my wish to direct attention more especially to the latter difficulty, having myself witnessed some instances, and having been informed of many others, wherein the parents have regarded the health and lives of their children so little, as not only to despise the security afforded by Vaccination, but to omit the most ordinary precautions against Small Pox infection, and to reject the gratuitous medical assistance which was within their reach.^[1]

But there are links by which all the various classes of society, from the highest to the lowest, are connected; and it is through the medium of these that we must hope for the removal of the difficulties referred to. There are few of the rich, who have not the power of influencing some of the poor, nor do I believe there are any of the latter who may not be influenced by some one or other of the former. Whether this influence may be exerted through interest, through persuasion, or through the conviction of reason, is a matter of less moment than the attainment of the end in view—namely, to induce all, without exception, to have their children vaccinated during infancy—and were it employed in its fullest extent, this end might certainly be accomplished.

It hence becomes of the utmost importance, that those should themselves be convinced of the true value of Vaccination, who may possess the power, by whatever means (never omitting, however, when possible, to do it through the medium of reason) of extending the operative influence of their conviction to others. From the wealthy, the intelligent, and the educated parts of society then, I venture to hope that the following Estimate will meet with some serious consideration, and that, in whatever degree it may directly contribute to remove doubt, it may, at least, excite such a spirit of candid and deliberate enquiry into the subject of Vaccination, as may ultimately render its great value universally acknowledged, and its practice in every instance adopted.