A system of practical medicine. By American authors. Vol. 1

by Unknown

Ordinarily, no effect whatever is observed until after the lapse of two or three days, when a red papule is formed. This papule increases in superficial area, but not in height, and gradually loses its redness. It assumes a circular form, or, in the case of a compound pock (for that is the proper name for the lesion), a configuration representing segments of several circles, and as it increases in area it becomes more and more raised at the border (the bourrelet of French writers), while the central portion, which also increases in size pari passu with the peripheral annular vesicle, does not become more elevated, but remains depressed, giving the pock as a whole the peculiar shape termed umbilication. Up to the eighth or tenth day, inclusive, the marginal elevation contains a limpid fluid termed lymph, and consequently presents a pearl-like lustre. At this period a rather sudden increase takes place in the corpuscular elements contained in the lymph, causing that liquid to become thick and opaque, so that the elevated margin of the pock, which before had shown the pearl-like lustre alluded to, now comes to look as if made of tallow.

At the same time what is known as the areola forms around the pock, and constitutional symptoms show themselves. The areola is a circumscribed redness of the skin, perfectly circular in form and of five or six times the diameter of the pock itself. It is sharply defined and of a vivid red hue. Usually it is a mere hyperæmia of the skin, but in some instances, especially where the process of pock-formation is decidedly pronounced, a few papillary elevations are to be seen in the immediate neighborhood of the pock, and at that situation there may also be some lividity. After a few hours' persistence in the form of a disc the areola begins to disappear, the redness fading first at the central portion, so that in its declining stage it assumes the shape of a ring which constantly grows narrower and narrower at the expense of its inner portion, and finally disappears altogether. In the cow the areola is only a faint line immediately around the pock.

Constitutional symptoms are invariably present in cases that follow the regular course. The temperature rises one or two degrees Fahrenheit, the appetite becomes impaired, and sleep is somewhat disturbed. In many cases, mostly those of secondary inoculation, the symptoms are more severe; the fever runs higher, and may be accompanied with transient delirium; nausea is experienced, perhaps with actual vomiting; and severe pain is felt in the head and along the spine, the latter being most marked in the cervical region. These symptoms usually last but a few hours, and they are apt to be accompanied by a modification of the areola whereby it loses its disc-like outline and becomes diffused irregularly, especially, if, as is usual, the inoculation has been done on the arm, in a downward direction toward the elbow.

Along with these phenomena intense itching is often felt at the situation of the pock, being an aggravation of the pruritus that in a mild form accompanies the greater part of the whole course of the lesion. Supposing the arm to have been inoculated, the lymphatic glands of the axilla now become swollen and tender, but their suppuration is unusual, and is to be regarded as a complication.

To go back to the pock: some time before the contents of the marginal elevation become opaque the central portion is converted into a crust of a brownish color, and finally, from the tenth to the fifteenth day, the bourrelet itself, having ceased to increase in size, takes part in the process of incrustation, the completed crust representing the form of the pock, having a circular ridge at the border, at which part its color is not so deep as at the centre. The crust usually falls off between the fifteenth and the thirty-fifth day. It is hard, translucent, and of a prune-juice color; thick at the centre and thin at the periphery; smooth on its attached surface and somewhat wrinkled on its outer aspect; surmounted at the centre by the epidermal débris produced by the operation of inoculation, mingled perhaps with more or less dried blood.

After the crust falls off a reddened surface is left of a cicatricial nature, usually somewhat depressed below the level of the surrounding skin, and frequently showing lesser pits, which latter appearance is termed foveolation. Instead of these pits, radiated striæ are frequently left. Gradually the scar loses its red color, and, like other scars, finally becomes paler than the surrounding skin. It is usually permanent.

IRREGULARITIES IN THE COURSE OF THE DISEASE.—Ever since cow-pox first became the subject of medical study deviations from its typical course have been noticed, and have been the theme of a good deal of speculation. The older writers, indeed, bestowed no little attention upon what they considered to be not irregular forms of vaccinia, but distinct affections with which it was liable to be confounded. Their descriptions of these diseases, which they termed spurious cow-pox, are, however, so vague as to possess but little more than an historical interest. In regard to affections met with casually in the cow, we can often determine their nature only by test-inoculations, and even that criterion is not always thoroughly convincing; for, on one account or another, we may fail in the attempt to propagate true cow-pox, and on the other hand, if we admit that there is a radical difference between cow-pox and small-pox, it is manifest, bearing in mind the errors into which experienced investigators have fallen, that we may propagate small-pox through a long series of experiments without once suspecting it to be anything but cow-pox. We may, nevertheless, always determine, provided we succeed at all, whether we are dealing with a disease that protects against vaccinal and variolous inoculation.

In the human subject we seldom meet with affections that counterfeit vaccinia, although, if we take only the lesion into consideration, there are certain contagious forms of herpes that may give rise to doubt, and possibly the same may be true of impetigo contagiosa.

Turning, then, to the irregularities properly so called, we have first to consider the absence of constitutional infection. This must not be confounded with the mere lack of obvious constitutional symptoms; what is meant by the expression is, that in certain instances the local lesion may appear typical, and yet no such impression be made upon the system as to render it proof against subsequent inoculation. Early in the century the possibility of this lack of systemic infection was insisted upon by Mr. Bryce of Edinburgh, who invoked it as an explanation of the occasional failure of vaccinia to protect against small-pox. The practical question was, how to decide, in a given instance, whether general infection had or had not taken place. In the opinion of many observers—and that notion has cropped out every now and then up to the present day—absence of the areola furnished at least presumptive evidence that the constitution had eluded infection. But, whatever may be held theoretically, it must be conceded either that the general system very rarely fails to feel the impress of the disease, or else that the criterion is fallacious. For in an experience of seventeen years the present writer has not known of a single instance in which a vaccinal lesion that pursued a regular course in other respects has failed to be accompanied by the areola. And certainly Mr. Bryce himself must have attached little if any importance to it, for he took great pains to establish a means of determining the presence or absence of constitutional infection—the so-called Bryce's test. This consists in repeating the inoculation at a certain period in the evolution of the disease, the theory being that systemic infection does not take place at once, but only after the lapse of a number of days from the time of the inoculation. Up to that time a repetition of the inoculation is possible, and, if systemic infection results from the first one, both lesions will mature at the same time, the second one following an accelerated course, reaching its acme rapidly, although dwarfed in size. If, on the other hand, the first inoculation failed to infect the constitution, the second one will pursue its course in the usual manner. Moreover, at a certain time, generally about the fifth day, a repetition of the inoculation will fail altogether if the original insertion has really infected the system. The present writer can testify that Mr. Bryce's statements are correct; he has applied the test in many cases, but in no instance has he been led to the conclusion that constitutional infection had failed to take place. He is inclined to think, therefore, that such failure is exceedingly rare.

Passing over the multiplicity of irregularities in the lesion that were described by the older observers, it seems that there are a few that are of practical importance. In the first place, there is a variety of pock to which it is not easy to give a definite name, but which is characterized by a lack of decided elevation above the surrounding skin (a deficiency for which it makes up in superficial area), by the early formation of a thin, flimsy, straw-colored crust, and by the utter failure of the characteristic firm brown crust of the typical variety to become developed. This form of irregular pock has not been seen by the writer of late years, but before animal vaccination came into general use he met with it frequently, mostly in cachectic children. Notwithstanding its sprawly, unsatisfactory appearance, it is undoubtedly genuine, for the typical lesion may be produced by inoculation with its contents.