144 Phenothiazine—A Remarkably Efficient Anthelmintic
The lamb that died as a result of repeated daily doses refused food for the
last day or two and showed a dark red diarrhoea before death ;* this lamb was
in a particularly poor condition when the treatment commenced, which may
have had something to do with the fatal result ; a second one in better condi-
tion, however, also showed signs of intoxication although it survived 16 daily
doses of 10 grammes.
Two other lambs which received daily doses of 5
grammes each showed no such symptoms.
SUMMARY OF OBSERVATIONS IN SHEEP.—Extensive trials suggest that in
doses of 15 to 30 grammes (0.5 to 1 gramme per kg. body weight) phenothiazine
has a remarkably good anthelmintic effect in sheep, the efficiency of its action
ranging round 100 per cent for worms in the fourth stomach and 80 per cent
for most of the worms in the small intestine. Where used in actual outbreaks
of parasitic gastritis its effect is reflected in very considerable gain in weight.
Less extensive trials suggest that doses as low as 0.08 gramme per kg.
body-weight have a considerable anthelmintic effect although the action of
larger doses is more reliable.
The tolerance of sheep is extraordinarily high, 400 grammes having been
given without ill-effect; a repeated daily dose of 10 grammes, however,
produced a fatal intoxication in one instance.
Sheep will take 2 grammes to 5 grammes mixed with the food, a good
anthelmintic effect being produced even by the smaller dose.
Administration is best carried out by means of 5 gramme tablets and a
rubber-ended balling gun.† Given adequate assistance it is possible for one
person using a balling gun to administer a 10-gramme dose to 160 lambs in an
hour.
Goats
Experiment No. 8.—The following observations were made on the effects
of phenothiazine on a group of goats at the Ministry's laboratory, many of
their number suffering severely from parasitic gastritis.‡
*Post-mortem findings in this sheep were as follows :—
Nasal passages filled with a catarrhal exudate of a pink colour, presumably due to
the inhalation of phenothiazine powder, the mucous membrane over the
turbinated bones and in the upper part of the trachea was of a dark reddish
brown colour, but apparently not inflamed, the coloration presumably
also being due to the formation of thionol from the drug. Bronchioles
also contained much catarrhal exudate. Liver showed signs of fatty
degeneration : the kidneys were of a dark red colour, the pelvis containing
a brownish liquid. The fourth stomach showed a slight inflammation of the
mucous membrane throughout its whole extent.
†In a private communication received since this was written, Dr. Robertson of the
Aberdeen School of Agriculture claims to have dosed sheep with the liquid form of pheno¬
thiazine at the rate of four per minute. McEwen and Rowlands also preferred the liquid
and as the tablets are very awkward to administer without the proper balling gun this
form of the drug may be found to be the most generally useful.
‡These goats had been collected from various centres in Wales, and in Ireland,
several of them being in a more or less advanced stage of parasitism on arriving at the
Laboratory. On account of their different origins, therefore, the nature of their helmin-
thic infections did not conform so nearly to one type as it would have done had they all
come from one source.