T. GRAHAME, D. O. MORGAN AND J. E. N. SLOANE 67
debilitated poor ' doers' had a low or almost
negative count, whereas many animals which
appeared to be in ' good condition' were heavily
infested ; these animals were treated.
Practically all the horses, whether in good or
bad condition, improved and gained in weight
following the administration of the drug.
All the animals chosen were infected with
strongyles and occasionally with ascarids.
ADMINISTRATION OF THE DRUG
The data on the use of phenothiazine as an
anthelmintic in the horse is somewhat scanty, and
the dosage, method of administration, etc. re-
quired further investigation. The first doses
given in the present series were based on 5 gm.
per 50 lb. body weight, which usually worked out
at approximately 100 gm. for the average
cavalry horse.
One hundred gm. of phenothiazine is a
bulky mass and its administration offered a
problem. The powder is not miscible in water,
but may be suspended and given by stomach tube.
The administration of the powder in the food
was tried with success. The procedure was to
feed a bran mash mixed with treacle, followed at
the next meal by a similar feed with which the
powder was mixed. Some animals reluctantly
ate the mixture, while others, especially the
' particular feeder,' left it. The following method
was found to be the most satisfactory. The
animals were made to miss a feed, and then an
ordinary bran mash containing the powder was
given. In almost every case the feed was eaten,
and there was no difficulty when a little boiled
oats was added.
It was the usual practice to treat the animals
at the week-end, missing the Saturday morning
feed and giving a meal containing the powder at
the mid-day feed. In this manner the usual routine
of work was not interfered with. The animals
were at their usual work on Monday, having
suffered no apparent inconvenience. However, to
prevent the working of any horse that might be
particularly sensitive to the action of the drug,
each animal was examined every morning for a
week subsequent to the administration of the
medicine.
REACTIONS OF THE DRUG
Some interesting observations were made which
seem to have a bearing upon the distribution and
possible ' breakdown ' of the drug in the body
system, although some horses showed little or no
departure from the normal.
(1) The conjunctival mucous membranes were
stained a yellowish colour and occasionally the
mucous membranes of the mouth and anus were
similarly coloured. The yellow coloration ap-
peared after 24 hours and sometimes became more
intense, but gradually faded out. In some, the
coloration disappeared in a few days, but in others
it persisted for seven to eight days and even longer.
The mucous membranes of the mouth and anus
were stained a faint yellow, very much less intense
than that of the conjunctiva.
(2) The urine of some horses was viscid
and coloured a reddish brown. Attention is
drawn to this condition by the staining of the
bedding and floor of the stable, and by the red-
bespeckled hind limbs, especially noticed when
the limbs have white markings.
The coloured excretions may persist for two to
four days. In several animals, the urine remained
coloured for several days before a clearance was
effected.
Those unaware of this action of the drug might be
alarmed and consider the reaction unfavourably.
Analysis of the urine did not show any unusual
ingredients, other than might be expected from the
' breakdown ' of the drug.
Technique. To measure the anthelmintic effi-
cacy of the drug, egg counts were carried out
before and after dosing.
The modified stoll dilution method was used
throughout: 5 gm. of faeces were weighed out
into a jar graduated at 75 c.c. and N.10 NaOH
added up to the 75 c.c. mark. The sample was
left overnight to soften, and after shaking and
sieving to remove coarse debris, 0.15 c.c. was
removed by means of a Macdonald pipette. All
the eggs in the 0.15 c.c. were counted and the
process was repeated three or four times, and the
average count taken. The figure obtained,
multiplied by 100, gave the number of eggs per
gm. of the original sample. Eggs of Parascaris
equorum were counted separately from those of
strongyle worms. The faeces were taken direct
from the rectum of each horse.
Explanation of Tables. Where a count of 30
eggs appears in the tables, this indicates that only
one egg was seen in the three slides examined. A
plus sign in the tables indicates that no eggs were
found by the above counting technique, but that a
concentration method using about 5 gm. of
faeces revealed a few eggs.
Owing to the transfer of horses, some irregularity
occurred in respect of the intervals of time between
the three counts after dosing. In Tables I, II, III,
VII and VIII, the counts were made at approxi-
mately two, four and six weeks after dosing, and
in Tables IV, VI, IX and X at two, three and four
weeks. In Table V, only one count was obtained,
and this was taken at four weeks. In every case
where a third count was obtained, it was taken at
not less than four weeks after the date of dosing.