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lymph immediately prior to its use in vaccination. In all respects
this additional experience has proved satisfactory. It comprised
17 vaccinated calves, the testing of the glycerinated lymph from
which involved some 250 plate cultures. Almost invariably agar
plates, inoculated, four weeks subsequent to collection and glycerination,
with samples of the lymph from these 17 calves, failed to
exhibit growth of extraneous micro-organisms. In the few
instances, in which microbic growth appeared on such " fourweek
plates," the resistant bacterium proved to be either bacillus
subtilis or bacillus mesentericus vulgatus, microbes which, as
later experience showed, may be practically excluded from lymph
by scrupulous attention to the cleansing of the vaccinated area
on the calf immediately antecedent to collection of lymph from
the vesicles.
"Dr. Blaxall has carried on a series of interesting experiments
on the viability of the tubercle bacillus in glycerinated calflymph
to which this pathogenic microbe had been purposely
and abundantly added; and on the activity qua vaccination of
samples of glycerinated calf-lymph which, after having been
found free of extraneous micro-organisms, had been subsequently
stored for considerable periods of time. He finds that the added
tubercle bacillus is invariably killed off by a month's sojourn in
this glycerinated lymph ; that after having been thus dealt with
it will not grow in its appropriate culture media, nor produce any
pathogenic effect whatever on the guinea pig. And as regards
the keeping quality of glycerinated lymph, he finds that at a
period nine months subsequent to its having been demonstrably
free from extraneous microbes, it is potent to cause in babies
vaccinia vesicles in 100 per cent. of the points at which it was
inserted."
Well worthy of attention at the present time is the
following
FACTS ABOUT SMALLPOX AND VACCINATION.
Issued by the Council of the British Medical Association,
December, 1897.
(1.)—The mortality from small-pox is much less now than in
prevaccination times.
(2.)—The greatest diminution in the small-pox mortality is found
in the early years of life, in which there is most vaccination.
(3.)—In countries where there is much vaccination and re vaccition
relatively to the population, there is little small-pox.
(4.)—In classes among which there is much vaccination and revaccination
there is little small-pox.
(5.)—In places where small-pox prevails it attacks a much greater
proportion of the unvaccinated than of the vaccinated,
especially where the vaccinations are comparatively recent.