OF THE VACCINE OU COW-POX,

M7

The contained fluid, instead of being limpid as usual, is now ant'then found opake.Spurious Pustules which afford no Security against the Small Pojr

The success of the operation is doubtful when there is any con-siderable deviation from the usual course of the disease; whetherpremature inflammation, irritation, itching, or vesication occurs ;or the progress of the vesicle is too rapid, its contents yellow oropake, its texture soft, its centre elevated, or its form not well de-fined; or whether a premature efflorescence takes place, and adistinct, vivid, circumscribed areola is wanting.

This anomalous vehicle, or spurious pustule, as it is called, ismore liable to be broken than the regular genuine vesicle, from itscentre being more elevated, and its texture less firm. When broken,it is frequently succeeded by ulceration; or by a light brown oramber-coloured creeping scab.

Probable Causes of Spurious Pustules.

Spurious pustules may be occasioned not only by matter takenfrom a spurious pustule, but also by matter taken from a genuinevesicle at too iate a period; or by that which has been injured hxkeeping, exposure to heat, or any other cause. They may also beoccasioned by using rusty lancets in inoculating; by rude and un-skilful methods of performing the inoculation; or by the genuinevesicle having been destroyed at an early stage, and the regular pro-gress of the disease thus interrupted.

The Methods of taking Vaccine Matter for Inoculation, and ofpreserving and conveying it.

Matter may be taken from a genuine vesicle at any time from itscommencement til! the areola begins to spread; commonly till theeighth or ninth day, sometimes later, but never after the areola isfully formed.

It is to be taken by small superficial punctures, made in severalparts of the vesicle with the point of a lancet introduced horizon-tally. Time should be allowed for the fluid to exude, which willappear on the vesicle in the form of small pellucid drops. If ne-cessary, very slight pressure may be applied with the flat surface ofthe lancet, to quicken the discharge.

Great caution must be observed in this process; or violent in-flammation and extensive ulceration may sometimes ensue.

The matter may be received on the points of common lancets,when it is designed for use immediately, or within a very few days;otherwise these instruments cannot with propriety be employedeither for the preservation or conveyance of vaccine matter, as whencharged with that fluid they soon rust. An ivory lancet is not lia-Die to this objection. It may be fixed in a handle, and screwednto a case, in order to exclude air.

A common method is, to take two small square pieces of glass,»n the centre of one of which the matter may be received, by ap-olying the glass to the vesicle, punctured in several places, in themanner before described, and covered with the fluid ; it may thenoe suffered to dry, and applied to the vesicle repeatedly. When