Inoculation, in medicine, is the transferring of distempers from one subject to another, particularly of the small, and cow-pox.

The practice of inoculation is of great antiquity in the East, whence it was introduced into Britain, early in the 18th century; though not without many struggles, and violent opposition, under the frivolous pretext, that it was contrary to the principles of Christianity, and usurping the sacred prerogatives of the Creator. On account of its superior utility, however, it has at length triumphed, and is now almost generally adopted, excepting among a few fanatics, who, from superstitious motives, confirmed by obstinacy and ignorance, still object to it as an unlawful, and even sacrilegious attempt. The curious reader, who is desirous to become acquainted with these objections, will find them stated, together with a defence of inoculation, in Di. Lettsom's Medical Memoirs.

Various methods have been adopted, for the artificial communication of the small-pox ; the most effectual of which appears to be that of making a puncture in the skin, or removing the epidermis of the upper arm with the point of a lancet, dipped in variolous matter.-For the proper treatment of persons during the progress of inoculation, the reader will consult the article, Small-Pox, where the comparative advantages of its recent substitute, the cow-pox, will be concisely stated.

Inoculation. To preserve mankind from the violence of this epidemic scourge ; or, at least, to mitigate its effects, various methods have been devised and practised. Among these, we shall take notice first of the int lation of the small-pot, by introducing the minutest portion of matter into the system, through a slight wound in the upper-arm, made, by a lancet or cautery. This bold and ingenious attempt has, doubtless, been the means of preserving innumerable lives, and may therefore be deemed a real benefit to society. With respect to the most proper season for such operation, Baron DimsDale has evidently proved, that the inoculation may be undertaken at any period of the year, provided the patient skreened from heat in the summer, and from severe cold in the winter, so that he may enjoy fresh, cool air, when no other epidemic diseases prevail: the most proper subjects are children after the second year (on account of the various affections to which infants are liable prior to that period), without rejecting scrophulous, scorbutic, and other habits.

Previously to the inoculation, the patient should, for about nine or ten days, adhere to a regular diet, avoiding all animal food, fat substances, malt-liquors (excepting a little small beer), seasoned dishes, wine, etc. while he subsists. on puddings, sago, fruit-pies, and vegetables of every description, but with great moderation. Baron D. farther directs the following powder to be given three times during this regimen, or every third night; and a dose of Glauber's salt to be administered every succeeding morning: Take calomel, and pulverized crabs-claws, of each eight grains, and two grains of sulphurated antimony, or 1 -8th part of a grain of tartarized antimony : - the quantity here prescribed, is for an adult, so that the 3d, 4th, or even 6th part, will be sufficient for a child, according to its age and sex. - The day after the third dose has been swallowed, will be the proper period for inoculation. But, if the patient be of a delicate, tender habit, especially females; or, if the blood be contaminated by disease, or intemperance, a moderate portion of animal food, and one or two glasses of a generous wine day, may be safely and advantageously allowed.

Towards the 5th or 6th day, a slight fever occurs, but which again subsides on the appearance of the pustules ; these, in the progress of several days longer, become more visible, particularly about the part inoculated ; pursuing, in general, the same course as the mild or distinct small-pox; and consequently requiring the same treatment, in its different stages.

Vaccine Inoculation.

One of the most remarkable and important phenomena, in the history of animal nature, is the cow-pox, which was first duly inquired into, and publicly announced in the year 1798, by Dr. JENNER, of Berkeley, Gloucestershire ; though it had for ages been known to dairy-men in the West of England. This malady appears on the nipples of cows, in the form of irregular pustules. - -From the observations made by Dr. JENNER, and subsequently, by Drs. Woodville, Pearson, and other medical practitioners, it follows, that persons inoculated with matter, taken from one of these pustules, are thereby rendered unsusceptible of small-pox infection, and the reverse. The experiments instituted with a view to ascertain this extraordinary fact, are too nu merous to be related in this place : let it therefore suffice to mention, that they have been repeated in different countries of Europe, and with nearly the same success. - Although many formidable objections have been started, both by physicians and others, against the introduction of a new contagious virus derived from brutes, into the human body ; yet we have the satisfaction to say, that the arguments advanced in favour of the new inoculation, are, in our opinion, conclusive. Indeed, a scries of fads duly authenticated, in many thousand instances, where the latter has proved a milder disease than the inoculated small-pox, cannot fail to convince the most determined sceptic; though a few rare cases should have occurred, in which, from accidental or unforeseen circumstances, the contrary effect has resulted. On the other hand, we are firmly persuaded, that those sanguine and noisy ad-vocates for the cow-pox, who, from selfish or interested motives, have thus evinced their eagerness of becoming conspicuous in its defence, by writing and publishing diffuse volumes of undigested matter, . have only contributed to their own notoriety, instead of more ef-fectually aiding a good cause. - Hence, the Editor of this Encyclopaedia is induced to repeat the remark he ventured to insert in the 2d and 3d editions of his Lectures on Diet, etc. that " it is of little consequence, whether the cow-pox originate from any cutaneous disease of the milker, or from the grease of horses." - In order to satisfy professional writers on this subject, in general, and one of the most voluminous late cow-pox historians in particular (who ha suffered himself to be misled in an unguarded hour, to substitute confusion of terms and ideas for logical deduction, and sarcasm for argument), we shall briefly observe, that there can be no doubt respecting the milder nature, and comparatively smaller degree of danger attending the new inoculation, provided it be conducted by able hands. Admitting, farther, that a close and perfect analogy subsists between the two diseases, (which remains to be proved) we trust, no medical philosopher would venture to pronounce every person thus inoculated, completely secure from the attacks of a future epi' demic small-pox, if the latter should appear, perhaps in another climate, or in that virulent form, in which it has sometimes occurred in Britain.

With the philanthropic view of extending the beneficial effects resulting from the new inoculation to the poor, a new Dispensary, termed the vaccine Institution, has lately been established in this metropolis ; where the operation is gratuitously performed, on applying to Mr. Lewis, apothecary, Golden-square; and where they receive every attention that circumstances may require; or, in eases of necessity, the patients are visited by medical gentlemen, who have benevolently offered their services for that purpose. - Lastly, we understand, that professional or other persons inclined to promote the inoculation for the cow-pox, may from the same quarter be provided with genuine vaccine matter, preserved on threads, and confined in phials hermetically sealed, at the reasonable price of half-a-guinea each.