A. D.
MACGREGOR
57
for other workers in India to attempt a closer
observation for clinical evidence of this pheno-
menon than has been applied in the past ; for it
may be accepted that a condition, of this kind,
which has been lying in apparent obscurity for
some 50 to 100 years, is not as obvious as the
proverbial haystack. It requires at times pains-
taking search to discover the primary and even
the later nodules, which, when burst, form a
sort of matted scab of no particular colour other
than that of the surrounding hair. The affected
sites and their appearance are probably better
studied from the accompanying photographs,
(Plate IX) although most of these are of animals
showing a much more prolific cutaneous affection
than usual. In most outbreaks the number of
clearly defined nodules or pustules has ranged
between 10 and 100 over the neck, withers,
flanks and/or lumbar region. Experimentally,
the evidence on this point is meagre and
ot very substantial yet, as only one ex-
perimental calf showed three initial nodules on
the neck some 14 days after inoculation with an
emulsion of the scab from a field case of the
disease, after developing an ordinary mild attack
of alimentary rinderpest with perfectly typical
mouth lesions. So that the exact period of
development of cutaneous lesions after infection
is not yet established ; it probably approximates
from seven to ten days.
However, certain other facts do stand out in
the preliminary work on this series of incidents :
(1) the scabs taken from the nodules of field
cases are infective and capable, when
emulsified, of reproducing rinderpest
(experimentally in three instances) and
even (in one case) of repeating what
appeared to be cutaneous nodules result-
ing in scab formation ;
(2) these scabs were capable of reproducing
true rinderpest even after some three
works from the date of their removal
from the animals in the field ;
(3) The blood from the calves so infected has
been found capable of reproducing
rinderpest in other calves experimentally
(once confirmed by Mukteswar and twice
by ourselves in Calcutta) ; and
(4) this cutaneous rinderpest eruption, as it
may
be called, is the undoubted cause of
a permanent
pitting of the skin (shallow
sauce
like depressions) which shows up
prominently in the treated hide, to the
extent of reducing the value by 40 per
cent or more. In the finished hide,
these depressions measure, when single,
the diameter of an ordinary green-pea,
but quite frequently one, two or even
more become confluent,
when the
damage to the hide is correspondingly
increased. Admittedly, the guilt attach-
ing to this cutaneous eruption as the
cause of such depreciation in hide values
was only proved in one case, in which
the animal affected was slaughtered and
the hide subjected by stages to tanning
processes, after careful mapping of the
original sites of the pustules. The
depressions in the finished hide corres-
ponded exactly with the pustule sites.
But there is little reason to doubt that
the same results will be obtained on
repetition of the experiment, which was
so carefully done with cooperation of
Mr Das Gupta, M.Sc., of the Bengal
Tanning Institute.
DISCUSSION
It is suggested that at this stage of the work
on what appears still to be an insignificant prob-
lem, it is not wise to draw conclusions, but it
cannot be denied that certain possibilities emerge
from the material facts now available. It may
be, for instance, quite reasonably held that where
cutaneous rinderpest prevails the concepts of
old regarding the spread and unaccountable
recrudescence of rinderpest in areas previously
presumed to be free require some form of reorienta-
tion ; that the mystery of the so-called spontaneous
rinderpest, so long unsolved as to its source, is
now possibly given its conge; and that the
economic importance of rinderpest does not end
with the incapacity, or even with the death of the
affected animal, but permeates the hide industry
a most important threat to the country. Finally,
it seems necessary to add that, from the obviously
prolonged viability of the virus in these cutaneous
scabs, their potential danger is difficult to exag-
gerate, not only from the very common and
customary habit cattle have of scratching one
another with their mouths and thereby of ingesting
in this way the scabs carrying the living virus,
but also from swallowing during grazing scabs
which have dried in situ and later fallen on to the
pastures.
However, the presumptive evidence of this kind
is all we have at present to support the contention
referred to above that cutaneous rinderpest may
be fraught with all-important repercussions, such
as of explaining the so-called flare-ups of the
disease in apparently free areas, or even of the
rather unbelievable possibility of recovered
animals being so-called carriers or rather vehicles
through their scabs of the disease. Still, even
after allowing that all things are possible, it seems
reasonable to expect that where cutaneous
rinderpest occurs, a higher degree of immunity
among such local cattle should prevail; for it