TREATMENT OF BOVINE NASAL SCHISTOSOMIASIS
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the operation is at all necessary. Much care, no doubt, is necessary to prevent
the solution escaping into the perivascular tissue, the chances of which are ob-
viously greater if five minutes are taken, instead of as many seconds, to complete
the operation. In actual practice, it is not possible for one to take such a long
time for each injection when many animals have to be done in a day. Hornby
[ 1921 ] used a 4 per cent solution for intravenous injections and appears to have
finished the operation rapidly with no ill-effects. Other workers such as Richardson
[ 1928 ] and Holmes [ 1921 ] have also used a 4 per cent solution or even a little
over, without any bad results, but the dose they all gave appears to be not more
than 2 5 grains per 100 lbs. body-weight. In the experiments done here, a 6 per
cent solution was injected fairly rapidly into the vein in the animals treated and
no ill-effects followed. It has already been pointed out, that even 15 per cent
solutions have been injected by the previous workers without any ill-effects.
It, therefore, seems clear that it is not the dilution of the drug that causes accidents
so much, as the dose and its repetition. A dilute solution may perhaps cause
a less intensive tissue reaction than a more concentrated one, if by chance, it
escapes into the perivascular tissue.
Elimination of tartar emetic from the system
Therapeutists admit that tartar emetic is a cumulative drug, though less so
than arsenic. Clark [ 1932 ] says that antimony unlike arsenic is rapidly ex-
creted and there is less tendency for cumulative poisoning to occur, when the
drug is given intravenously. He further says that 30 per cent of the drug is
excreted through the urine and it is not known how much is excreted in faeces
when it is given intravenously. Faust and Maleney [ 1924 ] say that a large
proportion of the drug is excreted by way of the intestines. Edwards [ 1928 ]
says that the drug is not discernible in the blood stream three days after intra-
venous administration. Krishna Iyer and Sarwar [ 1935 ] say that in two days
time, it is excreted completely. Hence, it is clear that a therapeutic dose given
intravenously is excreted rapidly and theoretically speaking, it should be possible
to repeat this dose in three days. But practical experience has shown that death
may be caused, if the same dose is repeated after a reaction has been obtained
to the first dose. Such a thing did happen in Bullock No. 3, even when the interval
between the two doses was a week and also in Bull No. 7. The symptoms of
reaction observed in the experimental animals were (1) a rise in temperature,
(2) disinclination to move, (3) weakness of pulse, (4) loss of appetite, (5) dryness of
the mucous membrane of the mouth and nose, and (6) unsteadiness of gait. These
symptoms persisted for about four days. If these symptoms are encountered in
an animal after injection of the drug, it indicates that the limits of a therapeutic
dose have been transgressed and those of a sub-lethal dose have been reached.
In such cases, if the dose is repeated before or soon after the signs of reaction have
subsided, accidents are likely to occur : at any rate, it is an indication, that sub-
sequent doses should be smaller in order to avoid untoward results,