Distribution of Leprosy. 129
This whole question deserves fuller consideration. Since
vaccination is said to diffuse leprosy in India, the first point to
be enquired into is the method employed. Anti-vaccinationists
are accustomed to speak of the danger of spreading the disease
by means of vaccination, as though the method of protective
inoculation were uniform, and as though vaccination were ex-
clusively practised from arm to arm with human lymph, or from
arm to arm.
If leprosy be transmissible in this manner, it can only be
by vaccination with human lymph or through the use of un-
clean instruments. Now in the city of Bombay calf lymph is
exclusively used, at the present time at least. In Madras the
Government has also determined to introduce as rapidly as
possible a complete system of vaccination involving the use of
animal vaccine to the entire exclusion of human lymph, and
similar steps are taken in other parts, as in Bengal, Assam,
and Burma. There is also no doubt that calf lymph is at pre-
sent extensively used all over India. Hence in calculating the
chances of spreading purely human diseases by means of
vaccination allowance must be made for the fact that a consi-
derable number of persons by being vaccinated do not expose
themselves to any such risk, for the danger of an infection by
means of unclean instruments is infinitesimally small, and can
therefore be disregarded. Such an event presupposes that the
person undergoing the process of vaccination is a leper, and
this in the case of infants and children, to begin with, must
be an extremely rare occurrence, and hardly more frequent in
the case of adults. Again, it is more than probable that in the
event of a confirmed leper offering himself for vaccination, the
most neglectful operator would be roused to the most careful
performance of his duty. Finally the person vaccinated from,
or after, a leper must be in the proper state or predisposition
to be infected by leprosy. The simultaneous occurrence of
all these concomitant conditions is hardly conceivable.
It is impossible to state in figures to what extent animal
K