difficulty distinguished from it. Whether it be from any spontaneous change in the nature of the morbid action in which Variola consists, or whether it depend on the influence of external circumstances, it is alleged that the late epidemic affections of this kind, have exhibited certain modifications of symptom and history, which entitle them to be set apart from the well known and regular forms of ancient Small-pox by a peculiar and specific title, and the above term, Varioloid, has been chosen as significant, both of the resemblance and dissimilarity. It was first used by Thomson, in his "Account of the Varioloid epidemic," which prevailed at Edinburgh, in 1818. Cross gives an excellent history of a similar epidemic (which, however, he terms Small-pox) as occurring at Norwich. The same pestilence, it is asserted, raged about the same time in France, Italy and Germany, from which last source it was brought into America in 1818, making its first invasion in Baltimore, (Md.) and Lancaster, (Penn.) It was first noticed in Charleston in January, 1824, and proceeded slowly to infect individual after individual, until November, when it spread more extensively. During that winter, it seized considerable numbers, but scarcely prevailed at any time so widely as to deserve the appellation of epidemic, and, in almost every instance, could be traced to a direct communication. After its first introduction, too, into our city, it should be observed that there were repeated arrivals of infected vessels, bringing hither persons actually ill of Smallpox or Varioloid. Nor was it long confined to the cities on or near the sea-coast, but was conveyed to several points in the interior, spreading, wherever it was known to be introduced, a degree of terror proportioned to the anticipated evils which are always expected to follow in the train of a malady so loathsome and devastating. In the spring of 1826, it prevailed to a sufficient extent among us to be regarded with special attention, but its principal sway as an epidemic was developed in the winter of 1830-31, during which it invaded every quarter of our city, and, indeed, almost every family, attacking all classes of persons, respecting no measures of precaution, nor repelled by any imaginable prudence in avoiding exposure.

It is reasonable to ask, and the community has a right to know from physicians, who use the term, what are the specific and characteristic marks by which Varioloid is distinguished from Small-pox, if it be thus distinct. In entering upon this subject we are at once surrounded by all the elements of animated controversy, and even hot dispute, and while we proceed in the fulfilment of our duty to express our opinions, we shall do this as

briefly as is consistent with perspicuity, and with all deference to the authorities with whom we are at issue.

Varioloid has been assumed to differ essentially from Variola (Small-pox) because, first, it affects persons known to have previously passed through attacks of regular Small-pox; secondly, it affects persons previously vaccinated; and thirdly, it presents certain peculiarities of history and character, which serve as distinguishing marks.

The first of these alleged reasons is obviously of no force. It was long since observed that Small-pox sometimes failed to destroy the liability to its own recurrence, and instances of its repetition are to be found in all the old writers. "Petrus Borellus," says Heberden, "records the case of a 'woman who had this distemper seven times, and catching it 'again, died of the eighth attack." Dr. Oppert, of Berlin, relates the case of a girl, who, at six years of age, had confluent Small-pox. Seventeen years after, she was again attacked, and died of the disease. A similar case is authentically stated to have occurred in this city. If it is replied, that these cases are too few in number, to affect the general rule, that Smallpox invades the constitution but once, we readily acknowledge the correctness of the assertion, and proceed to apply the inference to the case before us. During the prevalence of the late epidemic in Philadelphia, (call it Varioloid or Small-pox,) but sixteen persons are reported, by Drs. Bell and Mitchell, as attacked with it, who had previously had Small-pox. A similar list may be made out of cases of the same kind occurring here, while the pestilence prevailed among us, so limited in number, however, as to prove most conclusively, that Variola protects, at least in a certain degree, from Varioloid disease.

With regard to the second point mentioned above, it is only necessary to observe that no well informed physician of the present day, retains any confidence in the absolute preventive power of vaccine against the invasion of Small-pox, however much he may be disposed to confide in its unfailing modifying influence. But of this, more hereafter.

Thirdly, the principal peculiarities which are supposed to characterize the Varioloid, and to offer specific marks by which we may discern it, are, so far as we have been able to collect, the following:

First, the eruption comes forth in successive crops.

Secondly, the pocks or pustules, when formed, are conoidal, without a central depression.

Thirdly, they are vesicular and not multicellular as in Small

pox.

Fourthly, they are smaller than the variolous.
Fifthly, they contain lymph and not purulent matter.
Sixthly, they dry and fall off without pitting.

Seventhly, their progress and maturation are unattended with secondary fever.

To all these we would rejoin, that the circumstances above described, are by no means regular or connected in their occurrence, and that if they were, they would not imply sufficient distinction to constitute a separate form of disease. For,

First, in the Sinall-pox, the eruption is sometimes incomplete at first, the pustules appearing to thicken as the disease progresses: and it is well known to all nurses, to be easy to increase, locally, the number of pocks by exposure of part of the body to long continued heat, as by lying on it, wrapping it, or exposing it to the heat of a fire.

Secondly, thirdly and fourthly, the size and configuration of the pustules vary much in the most clearly defined cases of Small-pox. Upon the same individual, some will be seen large, and others small, some conoidal, and others depressed in the centre. The internal construction of the pustules will be found to differ in a corresponding manner; the conoidal are vesicular-those which present the depression in the centre are, like the Vaccine, multicellular, that is, divided into many separate cells or spaces. If we have not grossly deceived ourselves on many occasions, we have further noted that the pock changed its appearance in this regard during its progress; at first vesicular and conoidal, it exhibited afterwards a depression at the apex, becoming flattened and multicellular. But upon this, as it is by no means important to the argument, we shall lay no further stress, content if we can draw the attention of the profession to it by our remark.

Fifthly, as to the assertion, so often repeated, that it is characteristic of the Varioloid vesicle to contain lymph or serum, and not pus or matter, as the common phrase is, we will affirm, on the other hand, that the Small-pox virus is limpid and colourless. The most experienced inoculators, as for example Parr and the two Suttons, always preferred clear transparent lymph. It is in the latter stages of the pock, after common inflammation has supervened upon that which is specific and peculiar, that we find purulent matter; and the few cases of Varioloid or modified Small-pox, which run on into this stage, exhibit just as distinctly the formation of pus. If the inflammation of the skin be stopped at an early stage we prevent this:

and such, as we shall hereafter shew, is the most important of the train of effects attributed to the Vaccine.

Sixthly, John Hunter has somewhere declared, that in each pock of the variolous eruption a slough of the cutis vera, (the true skin,) takes place, answering in dimensions to the size and form of the pustules. This sloughing forms the pit or depression left by Small-pox, and the circumstance is assumed by him and others, Ring, for example, and Dr. Adams, to be peculiar to, and diagnostic of Small-pox, and to depend, not upon the intensity of the inflammation, but on its specific nature. Thus they propose to separate Varicella, or Chicken-pox from Variola, or Small-pox. It is easy however to demonstrate the fallaciousness of this test, supported as it is by the authority of such high names. A pit is not made by every Small-pox pustule.* In distinct Small-pox and in inoculated persons, there is frequently left no mark or trace of the location of a pock. Nor can it be doubted that the Chicken-pox and the (so called) Varioloid, occasionally, though seldom, produce similar sloughs or depressions, and so leave marks on the faces of those who have gone through an attack.

Seventhly, Secondary fever is often wanting in the mild cases of distinct Small-pox, and very rarely occurs in the inoculated. Dr. Parr indeed mentions the absence of it as a peculiar character of inoculated Small-pox. It is clear then that no inference can be drawn from its absence, of a nature favourable to our opponents. It arises like the secretion of pus from the irritation of the cutaneous surface, and is proportioned in degree to that irritation. It is therefore met with now and then both in Varicella and Varioloid.

We believe Varioloid to be identical in nature with Smallpox, because they are promiscuously capable of producing each other. The modifications which have been noted and discussed, we attribute in a vast majority of the instances presenting themselves at the present day, to the influence of Vaccine, of which we shall speak presently. In others, for they are confessedly irregular, to certain indefinable and varied peculiarities of constitution, or habit or condition of body in the affected subject.

Goethe. When a child, at Frankfort, he speaks of the invasion of an epidemic distemper-it was the Small-pox. Several persons who had been inoculated having been attacked by this dreadful disorder, people still hesitated to adopt that preventive. He was attacked-long ill-but had the good fortune to escape with out being disfigured.

Mary, Queen of Scots, so remarkable for her exquisitely fascinating beauty, had the Small-pox in her early childhood-but, says Bell, "it must have been of a particularly gentle kind, having left behind no visible traces." Bell, p. 54.

Under this head of Varioloid, we unhesitatingly coincide with Dr. Thomson in comprising Varicella, Chicken-pox. This gentleman entered upon the course of observations upon the Edinburgh epidemic, made by him with so much care and nicety, a thorough believer in the opinions of Heberden and Williams with regard to the separate and independent nature of Chicken-pox. His candour however, did not long permit him to remain the advocate of this view of the matter. "During 'the epidemic I had occasion," he says, "to observe natural 'Smail-pox, modified Small-pox, and the disease which I had 'been accustomed to regard as Chicken-pox, co-existing in the same situations, and appearing in their progress to produce one another. In three families in particular, situated at a con'siderable distance from one another, and between which, ex'cept through their medical attendants, no sort of intercourse had existed, my attention was strongly excited by observing 'Chicken-pox arise in unvaccinated children from the contagion ' of malignant small-pox. The occurrence of this event in circumstances which left no room for doubt, because there ap'peared to be no possible source of fallacy in the observation, 'led me to conceive that all the various appearances of the 'epidemic, in the different classes of persons whom it attacked 'might be produced by the operation of one and the same con'tagion."

Phenomena precisely similar, occurred under our observation in several families, whom we saw taken ill in succession, of the eruptive disease, which has prevailed in this city-call it what you will. Such of them as had not been previously vaccinated, or had not had the Small-pox, exhibited, for the most part, the regular symptoms of Variola as it is found described in the books and recognized by the best authorities. Those, on the other hand, who had been protected by either of the above means, had the disease modified variously, and in different degrees of mildness, some of them scarcely, others not at all distinguishable from Varicella. That the same contagion is capable of producing these several forms of variolous disease, whether regular or in any manner modified, is not only proved by their occurring thus together spontaneously, or in the natural way, but has been definitely established by repeated inoculation with the matter of the modified vesicle Varioloid or Varicelloid, in which, regular weli marked Small-pox was the result of the insertion of the virus. Among such examples the case of Dr. Hennen's son, of Edinburgh, is most worthy of being detailed. This boy, from whatever source infected, was seized with an eruptive disease, concerning which Dr. Thomson thus explicitly expresses himself: