PERMEABILITY OF THE GOAT'S PLACENTA TO RINDERPEST VIRUS.
65
is impermeable to most antigens and antibodies. Kraus [1901], for instance, re-
ported a negative placental transmission of haemagglutinins to the red blood cells
of the sheep from a mother goat to her kid. Kreidl and Mandl [1904] obtained
similar results with ox blood haemolysins in goats. Famulener [1912], as a result
of his experiments with haemolysins, concluded that goats actively immunised
against sheep blood corpuscles during gestation transmit the specific haemolysin
to the young, not through the placenta but through the colostrum. Reymann
[1920], in a study of natural agglutinins with B. typhosus, B. coli and horse and
rabbit sera, in a series of 14 goats and new-born kids, found the blood of all but one
kid negative. Similar results have been obtained with tetanus and diphtheria
antitoxins. The only substances to which the goat's placenta has been shown to
be permeable are thyroxin [Tanberg, 1922], insulin [Pack and Barber, 1928] and
iodides of potassium and sodium [Copper, 1906].
It is generally held that the placenta, speaking non-specifically, is, as a rule,
impermeable to foreign proteins and bacterial antigens. Filtrable viruses, however,
appear to be refractory to this law and occupy a position different from that of the
bacterial antigens in this respect. Burckhardt [1879] had long ago observed an
acquired immunity to variola in infants born of mothers during late pregnancy.
Transplacental infection with the now well-recognised tuberculous ultravirus has
been shown from time to time in rodents and there are on record a few cases of true
(with uninjured and apparently healthy placenta) congenital tuberculosis in the
human beings, although such cases reported in cattle, when examined casuistically,
appear to have occurred only through diseased placentas. Remlinger [1919], in
a study of the hereditary transmission of rabies, observed the presence of rabies
virus in the offspring of female guinea-pigs born either before or after the mothers
had developed symptoms of rabies. Beller and Tahssin Bey [1926] not only
succeeded in infecting the foetuses of pregnant sheep with pleuro-pneumonia virus,
but found the foetal tissues to be a suitable medium for the growth of that virus.
EXPERIENCE GAINED AT MUKTESAR.
It had already become evident from the researches conducted at Muktesar by
Dr. Edwards [1927] in connection with the " fixation " of rinderpest virus in preg-
nant goats that, when inoculated on the foetal side of the placenta, the virus could
be obtained from the maternal circulation. That the reverse is also true has now
been shown when an opportunity was afforded, on June 6th, 1933, through a nearly
full-grown foetus thrown by a goat a week after inoculation with a strain of the
" goat-adapted " rinderpest virus. The spleen of the aborted foetus was removed
with aseptic precautions, mixed with a quantity of the foetal blood, triturated with
sterile normal saline solution and inoculated subcutaneously into two fresh goats.
Both of these having reacted, the spleen of one of them was removed five days after
inoculation, triturated with saline and inoculated into two Himalayan bulls. The
bulls exhibited a typical thermal response, one of them having diarrhœa and the
E