East Saginaw courier. (East Saginaw, Mich.) 1859-18??, 1865-05-10

sociation.
RE-VACCINATION.
Several governments, confident in
the anti-variolous power of vaccina-
ton, and profting by the experience
gained, determined upon re-vaccina-
ton as the most likely means Of get
ting rid of the epidemics which were
desolating their armies. The effect
was SO salutary as to have finally BAN
ished smallpox from among them
But this was not the only benefit
Knowing, as we do, that smallpox
and cow-pox arc in reality the same
pprfived Of It's virulence by having pre-
viously passed through the system of
the COW, the results Of these numerous
re vaccinations are Of immense impor-
tance, not only in confirming the iden-
tity of smallpox and cow-pox, but in
establishing the no less important
fact, that the protective power OF
smallpox itself wears out of the sys-
tenn in certain proportion Of cases,
as life advances, in nearly the same
ratio as that of cow-pox. Thus, in all
these armies, certain proportion of
the men were found to have been pre-
viously vaccinated, while no inconsid-
erable proportion had passed through
unmodified smallpox. Now, if we
take the susceptibility to re-vaccina-
ton as test of liability to varioid,
or to second attack of smallpox, we
have these vaccinations proving the
fact that after a certain number oi
years, the same proportion of those
who had previously had smallpox bo-
como susceptible TO second attack,
as those who have been vaccinated are
to variolid. So that once having pass
ed through all the dangers Of unmod.
flied smallpox, the person, at the end
of twenty years, for instance, has no
better security against second attack
than the person who was been vaccin-
ated for corresponding length oi
time. The conclusion elucidated from
the data given, are
/. That vaccination is immensely
protective against epidemic diseases
generally, and against smallpox in
particular, and against death by small.
pox, the protective power of vaccina.
ton is almost perfect
2. That of any number Of persons
who have had unmodified smallpox
the proportion wholly protected from
a second attack ut adult age is 43 PEI
cent, while rs per cent are liable to i
again in somo form or other.
3. That out Of any number Of adul
persons who have good marks of vac
cination; 40a per cont. are perfectly
protected, while 59a per cent. are sus
lcobtible to variolid, or to re-vaccina
| ton to such degree as to render
their protection perfectly complete.
/ 4. That tho degree of protection af
fordeGi I ~ ! previous inmodifed small !
nor from a second attack, Is only z
per cent. greater than tho prOtectioi
afforded by vaccination; proportion
| too small to be regarded as any evi
dence of real difference in protective
power, and reasonably attributable Il
spurious or impaired vaccination iron
| a variety Of causes, such as vaccina
ton during the progress of other dis
eases, injury to the vesicle or defect
i've lymph.
s. That out Of any number OF adul
persons with imperfect marks of vac
cinetion, 23 per cent. only are pro
. tected, while ~ per cent. are liable
smallpox or varioled.
6. The liability to variolid after te
: years of age of persons yaccinate
under three years of age, and the in
creased liability again from fifteen I
twenty five years of age of person
!. vaccinated or re-vacoinated at fror
ten 10 fifteen years of age, demon
4 strates that, generally, protection b
vaccination under IS years of ago
d complete for about seven years onl,
!, Subsequent to twenty five years
= age, protection is complete for a grea
or len0th of time. prUportionate to I'll