CALCUTTA AND THE SUBURBS.                          3

Remarkable ab-
sence of the dis-
ease. 

The existence of
some general in-
fluences deter-
mining the pre-
valence of small-
pox probable.

Suburbs have been reported by the police, and no other deaths from small-pox
are known to the department. The deaths in Calcutta took place in April,
May, June, July, January, February, and March; for five months there seem to
have been no deaths. It is evident that we are now passing through a cycle in
which small-pox is at its minimum; after the epidemic of 1869-70, which was
so controlled by vaccination as to appear only in shadow without the terrible
ravages of its usual reality. This circumstance is deserving of very particular
notice. That there should be few deaths from small-pox two or three years after
an epidemic, when many thousands of persons had been protected against a
recurrence of the disease by an attack of small-pox, was a subject of easy
explanation. That an epidemic appearing only in outline and not affecting any
considerable number should be followed by a similar fall was not to be expected.
The happy result which is now noted seems to point in the direction of some
much more general causes operating to diminish an epidemic tendency, and
taking place equally after an epidemic year, whether the mortality occasioned
has been great or little. It seems preferable for the present to take this more
extended view of the question, than to attempt to explain it by any improve-
ment in the state of protection conferred by vaccination. Future years will
show how much can be effected in this way, even in seasons when small-pox is
not epidemic; but knowing the broad fact that these periods of inactivity of the
disease have always constituted a prominent feature in its natural history, and
not being able to convince myself that any measures have this year come into
more successful operation to account for the usual decrease of small-pox, I
hesitate for the present to regard the decline of the disease during the last year
as due to anything but obedience to the laws regulating prevalence.

Small-pox in Cal-
cutta during the
last 35 years.

Causes of recent
immunity.

6. Decrease of the mortality from small-pox in Calcutta.—From the 1st of
July 1837 to the 30th June 1865, 20,549 persons died of small-pox in Calcutta
within the muincipal limits. The average annual mortality during these 28
years is thus 733.89. The fearful mortality in the beginning of 1865 seemed
to me to point to a favorable opportunity for reviewing the whole system of
vaccination at the Presidency, and the most happy results have followed on the
introduction of the changes which appeared to me to be called for. I do not
propose, till I have had the experience of a full decennial period, to attempt any
critical examination of how the results to be presently brought forward have
been attained to, and content myself by the general statement that it has been
almost entirely due to thorough system and organization, and minute attention
to detail. I have been much disappointed in being able to note only a small
diminution of the mortality owing to the prohibition of inoculation, which I
was fortunate enough to secure. I think I can already notice an improvement
from the great efforts which have been made to protect the country round
Calcutta.

Saving of human
life effected

With the exception of the introduction of the class of head vaccinators
(the non-commissioned officers of the department), the establishment which has
last year been employed may (stating the fact generally) be said to be the same as
that employed in 1864. As the whole of the Suburbs have been included in the
area within which the establishment works, even the apparent increase of the
establishment for Calcutta of the head vaccinators is unreal, as taking all things
into account, the establishment working within the municipal limits of the town
has been not only virtually, but actually, lessened. The deaths from small-pox
during the seven years extending from 1st July 1865 to 30th June 1872 have
amounted to 398. The average annual mortality has thus been reduced from 734
to 57, that is, to less than a thirteenth of what it used to be. On an average 677
lives have thus been saved every year, or a total of 4,739 during the seven
years. This immense saving of human life would certainly have formed subject
for congratulation even had it been arrived at by greatly increased expenditure.
When it is considered that the expenditure, even when that for the Suburbs
(which yields its own return in saving large numbers of extra human lives
outside Calcutta,) is taken into account is virtually the same, possibly some
might consider the object attained in an even more satisfactory light.