Not infrequently, however, rudimentary forms are seen on closely observing the course of vaccinia, resembling the original eruption only in time of appearance (fou•th period), and to a certain degree in localization (extensor surfaces, face and back), while the outline of the efflorescence:: is very indistinct.
Personally I have observed thirty-two cases of general exanthem following vaccination, twenty-one of which occurred between nine and eleven days. In one case closely resembling variola, there were seen covering the entire body virulent, partly paptdar, partly vesicular efflorescences. (See the colored reproduction.) In the majority of cases the exanthem resembles that of measles. The papules, however, arc harder, and the mucous membranes are free from the exanthem. For a few days new crops appear, and the originally yellowish-red color of the papule gradually fades. All symptoms disappear at the end of a week. Aside from itching, there are no subjective symptoms, and no rise of temperature.
Eruptions appearing later (about the fourteenth clay) resemble lichen, and are usually regarded as an accidental appearing of lichen urticatus.
There is no treatment necessary in vaccine exanthem; if the itching is annoying, apply some powder or a solution of menthol. Abnormally high fever is not so infrequent. It is especially apt to occur in robust older children. It may then, as illustrated below, begin as early as the second stage. It need, however, not cause alarm; only when the tem perature does not decrease in the fourth stage should we think of the possibility of secondary infection (erysipelas, or more often measles or varicella, acquired from other children at the time of vaccination).
Cachectic rather sluggish reaction is apt to follow vaccination in anTinic or cachectic children. In these cases, the papule develops slowly, while there is no hyperaemia at all or but faintly ap parent for a few days. The areola appears later and the papule becomes broader than usual, and ordinarily in these cases there is but a slight rise of temperature.
the inoculations for a number of clays in different places, we can ascertain the action of the vaccination and study the relations of immunity. The first revaccinated places develop slowly in the same manner as at the primary site, but as soon as the first vaccination reaches the third stage the areolar hyperaemia at the same time surrounds all papules, and all become yellow and dry up simultaneously. The places inoculated later differ from the first only in size, as their development is retarded and they are much smaller. When the primary vaccination has reached the third stage, subsequent vacci nations do not reach the stage of papule formation. They show the early reaction. Without a latent stage, there appears within twenty four hours a small insignificant papule which soon disappears. The same phenomenon is observed, as a rule, when we revaccinate a few months after the first vaccination. In order to see the faint reaction, the site of vaccination must be inspected after twenty-four hours. By the time of the customary inspection (after seven days) it has entirely disappeared. Clinically, it is of no importance. but of great pathological interest, as it
explains the nature of vaccinal immunity, which consists not in an entire insusceptibility to vaccine virus, but in an immediate destruction of the same.
The organism, which after the first vaccination permitted the virus to develop and destroyed it after a period of eight to ten days (about this time the virulence of the vaccine vesicle disappears), now suppresses the disease in its very beginning, and removes the small amount of foreign bodies without any constitutional disturbance, while in the case of first vaccination, especially of variolation (inoculation of smallpox) the micro-organisms have become greatly multiplied, before the fight begins.
The immunity which vaccine affords against variola apparently depends on the same principle, namely, that the virulent variola micro organisms invading any mucous membrane are at once attacked and destroyed before they have multiplied.
The degree of early reaction depends on the dilution of the lymph, while the degree of the first reaction does not depend on the material used. In revaccination, the greater the dilution of lymph, the less marked are the local symptoms, while in vaccination for the first time, the development is only temporarily protracted but not quantitatively retarded. One vaccination changes the reaction of the organism toward the subsequent infection with vaccine or variola during the entire life. The organism attains a permanent allergy (allas—different, ergeia, mean ing reaction). A few years after the first vaccination, however, the pro tection is, as a rule, not sufficiently marked to destroy the infection within twenty-four hours, a few days being required by the organism. The longer the period after the first vaccination, the more frequently do we meet with forms of vaccinia, which, in the beginning, resemble the first vaccination but run a rapid course (accelerated reaction). Here also a vesicle is formed, passing through the same stages as the papule of first vaccination. The hyperemic zone, however (the aula), is generally irregular from the beginning, does not develop so rapidly, so that a sharp differentiation between the second and third stage becomes difficult, but the growth of the papule is completed earlier than that of the first vaccination, the retrograde changes more rapid, the exudate more superficial, so that the scars following revaccination are, as a rule, quite faint. The areola does not attain as great a diameter, although the physician is often led to regard the areola formation in revaccination as especially marked, owing to the fact that on the cus tomary day of inspection (eighth day) he finds the accelerated revacci nation at the height of development, comparing it with the appearance of the first vaccination which is still in the second stage and does not develop its full areola until a few days later. Occasionally, however, a very widespread hypermia is observed over the entire arm, especially in revaccinated adults, so that erysipelas is often suspected. The reason for this great susceptibility of certain people is not well understood.