Concerning those cases of generalized vaccinia that are manifestly not eruptive, it sometimes happens that the cutaneous receptivity is not exhausted for several weeks, or even months.
This test, however, is not altogether trustworthy, for a renewed susceptibility to vaccinia by inoculation does not necessarily imply that the liability to take small-pox by effluvium has been regained.
The most important sequela of vaccinia is the fact that it protects the subject against small-pox, and on that circumstance hinges the chief practical interest of the disease.
What has been termed generalized vacciniais another form of irregularity.
Besides immunity from small-pox, there are one or two sequelæ of vacciniathat deserve mention before we proceed to consider what it is better to class as complications.
Early in the {461} 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.
In the human subject vaccinia occurs generally as the result of intentional inoculation, as will be more fully referred to when we come to the consideration of vaccination.
The development of vaccinia is occasionally interfered with by an attack of rubeola; on the other hand, the two diseases may be seen running their courses together.
As to the eruptions due to vaccinia and vaccination, there can be but little doubt that these also have been frequently confounded with varicella.
When vaccination is practised after the disease is fully developed, the two disorders, vaccinia and variola, apparently concur, and proceed pari passu to the evolution peculiar to each.
The efficacy of universal inoculation of vaccinia as a prophylactic against variola is a question of scientific medicine to be decided on technical grounds and ought not to be a matter open to debate by the public at all.
In 1788 Jenner had a careful drawing made of the hand of a milkmaid suffering from cowpox to demonstrate to Sir Everard Home how exceedingly similar were vaccinia and variola.
To many of Jenner's contemporaries the view that vaccinia had at one time been a disease of human beings seemed unlikely; but we are now in a far better position to admit its probability than were those of Jenner's time.
Jenner believed vaccinia to be the same pathological entity as human smallpox, modified, however, by its transmission through the cow.
The identity of vaccinia and "grease" is certainly much more doubtful.
It is only when we contrast the loathsomeness and danger of smallpox with the mildness and safety of vaccinia and varioloid that we grasp the greatness of the work which Jenner did for mankind.
Cline inoculated a young tubercular patient with vaccinia and later with smallpox in no less than three places.
The word "vaccination" was coined by the French, so remarkable for the aptness of their descriptive terms, and it has ever since remained with us as a convenient expression for the inoculation of vaccinia as protecting from variola.
Now there is a disease of cows know as cowpox orvaccinia (from the Latin vacca, a cow) which is communicable to human beings.
The analogy between this process and the accepted view ofvaccinia is very close.
The view that vaccinia is attenuated variola is well known, and has been extensively adopted by English physicians.
The earliest use of the floral name Caltha occurs in Virgil's second Pastoral, "Mollia luteolâ pingit vaccinia Calthâ.
