According to the careful observations of Sobotkas, vaccination produces a polynuclear leucocytosis, appearing in the second period and rapidly disappearing on the seventh to the eighth day, often falling to below normal. This depression lasts three to five days and is again followed by a slight leucocytosis.
A thorough knowledge of the conditions as they appear a week after vaccination is of great importance to the physician. He then sees the development, at the close of the second or beginning of the third stage, of the umbilicated papule with a narrow red border or the com mencing areola. At this time a slight rise in temperature is the rule, and it is important to know that the real vaccination fever and the more marked local inflammatory symptoms appear later.
different forms of medication with purgatives, extensively practiced in olden times, are unnecessary. Nothing should be done for the fever. If the vaccination wound is scratched open, it is well to daily change the shirt and apply a dry powder (Zinc oxide 10.0, Talci 100.0) in small amounts to the wound. If the sores should suppurate longer than eight days (as a result of secondary infection), it is advisable to apply one per cent. peroxide of hydrogen followed by some bland ointment on a piece of linen. The dressing should be loosely fastened to the arm. Firm bandaging is harmful. The normal pustule which has not been scratched open does not need a bandage. The bathing of the children should be done cautiously between the eighth and fourteenth days to prevent maceration of the pustule. Bathing should be omitted in case the broken pustule is discharging.
The duration of the vaccinia depends to a certain degree on the intensity of the infection; the more virulent the virus, and the more numerous and larger the incisions, the more rapid is the course through the various stages. The use of diluted or old virus, which is reduced in strength, or small incisions causes the process to be prolonged for two or three days. (Nourney.) I have classified one hundred and thirty-nine eases of Nourney and myself, according to the appearance of the height of vaccinia (the end of the third stage) and the intensity of the infection.
Height on 7th, 8th, 9th, 10th, 11th, 12th, 13th, 14th, day.
From intensive vaccinia in per cent. of inoculated 1 24 From vaccinia with diluted lymph, few points by in oculation 6 71 24 From this simple retardation of the process for two or three days, we must distinguish the abnormally prolonged period of incubation, which, in my opinion, occurs when the bacteria enter the skin at a point which is unfavorable for their development. It is only by some mechan
ical imitation or the normal development of vaccinia performed later, that these "dormant bacteria" are awakened.
It was known to Sacco that the points of vaccination may remain latent for thirty days and that revaccination brings about their develop ment. If one week after vaccination no result is seen, it should not be taken for granted that the child is immune against vaccinia, but should be revaccinated. I have never had a case in which careful repetition failed to produce a reaction of the first vaccination. It seems, however, that in certain cases the skin has a tendency to render the bacteria in active or dormant. For example, in a child with myxcedema, vaccination had to be performed three times before it proved successful. Of sixteen incisions only four developed normally. One was negative, while the remaining were inactive until awakened by the development of the normal points of vaccination.
Not infrequently only a certain number of inoculated points lie dormant. They begin to develop a few days after those which have reacted normally and their course is much like that of post-vaccination. A small areola forms around them at the same time as around the pock which appeared earlier.
Accessory or Secondary Pocks.—In the third stage of vaccinia there appear in sonic cases within the areola, nodules of 1 to 2 mm. in (Ham eter, in one to two days they develop into umbilicated pocks, and dry up together with the original pustule. This phenomenon is of special interest as it reminds one of the inoculation with a mild virus, where it always occurred. The accessory pocks bear a certain relation to the virulence of the lymph. They do not affect the course of vaccinia and as a rule leave very superficial scars. Of greater clinical importance is the cow-pock, or vaccine exanthem, a general eruption which is a rudimentary form of the pock exanthem. After variola inoculation the general pock eruption appeared in the fourth period as the temperature began to fall, ten to thirteen days after inoculation. The individual efflorescences de v el op into real umbilicated pocks, followed by a sec ondary fever period. Similar genera] eruptions are quite frequently ob served when using a fresh variola vaccine, obtained after the variola culture has passed but once through the calf. It is extremely rare for a well developed v a ri of a-1 i ke exanthem to follow the use of our vaccine, which is obtained after many passages through the calf.