262
Anthelmintic Action of Phenothiazine
have been partly an apparent loss due to the fact that the lambs were weighed
on the first two occasions in the morning and on the second two occasions in the
afternoon and that in the afternoon they may have been emptier of grass and
water and therefore weighed lighter than they would have done in the morning.
But this could hardly have accounted for the whole of the loss of weight record-
ed, nor for the fact that the loss was twice as much in the group given copper
and nicotine. The main fact emerging from this experiment is, nevertheless,
that the total gain of weight in 30 days attained by the group given pheno-
thiazine was substantially greater (approaching twice as much) than that of the
group given copper sulphate and nicotine. This happened in spite of the fact
that only a small dose of phenothiazine was given, namely 5 grammes, whereas
10 to 30 grammes is a normal therapeutic dose. This experiment showed,
therefore, that, although at the end of the first ten days the group given copper
and nicotine (like the groups given copper sulphate only in experiments A
and B) had gained more weight than the group given phenothiazine, by the
end of 30 days the group given phenothiazine had done considerably better
than the group given copper and nicotine, and a good deal better than the
corresponding group in experiment A. This conclusion is supported by a
comparison of the composite egg counts. The small dose of phenothiazine
reduced this and kept it down at about the same level for 30 days, while copper
and nicotine (a normal therapeutic dose) did not appreciably affect it. It may
be noted here that Singer and Baker (1940. Cornell Vet. 30. 375-382) found
that phenothiazine was more effective than copper sulphate and nicotine or
tetrachlorethylene against nematode infestations of sheep.
Further experiments are desirable to ascertain the accuracy of the impres-
sion given by this experiment (and to a lesser degr ee by experiment A also)
that the effect of phenothiazine lasts much longer than that of copper and
nicotine. If this should prove to be true, the other experiments on sheep and
horses, described in this paper, will have an additional interest because they
show that egg counts reduced by phenothiazine do not necessarily rise again
for many weeks, although the animals are out at grass and are presumably
being continuously re-infested.
GOATS
So far only one goat has been available. This was a goat weighing 62½lb.,
belonging to a member of the staff of the Imperial Chemical Industries, Man-
chester. Samples of its faeces were sent by Dr. J. R. M. Innes, who subse-
quently dosed it with 10 grammes of phenothiazine without toxic effect.
Before the dose was given the faeces showed an egg count of 3,650 eggs per
gramme (average of two counts).
A sample of faeces collected 24 hours after the dose showed an egg count
of 100 (average of two counts). Fourteen days and eighteen days after the
dose the egg count was still 100 e.p.g. and 18 days after the dose it was 50
e.p.g. (average of 2 counts). Further samples of faeces will be examined to
find out whether the egg count, like that of the lambs and ewes described
above, will remain at this low figure for a considerable time.