NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
254
Anthelmintic Action of Phenothiazine
Swanson, Harwood and Connelly (1940) (J. Amer. vet. med. Ass. 96.
333-338) who studied the action of phenothiazine on Ascaris in pigs, used two
kinds of phenothiazine, namely, " conditioned " phenothiazine, containing a
dispersal agent to render it suitable for use as an insecticidal spray and
" recrystallised " phenothiazine, which was more effective than the " condi-
tioned " product. The writer is informed by Imperial Chemical Industries,
who supplied to the Agricultural Research Council the phenothiazine used by
the writer, that their phenothiazine, being a distilled product, can be regarded
as being as pure as the recrystallised product used by Swanson, Harwood and
Connelly.
SHEEP AND LAMBS
1.—EXPERIMENT ON TWO LAMBS AND ONE EWE
These three animals were kept indoors and in the same box throughout
the experiment. There was therefore the possibility that self-and cross-
infestation could occur. Egg counts were done daily on all three animals for
ten days before the phenothiazine was given and, with the exception of a few
days, for three months after the dose. The ewe was not dosed and constituted
a control.
On 2-11-39 the two lambs, called Marked and Unmarked respectively,
were dosed with the tablets of phenothiazine first issued by Imperial Chemical
Industries, namely, the 1 gramme tablets, each containing 1 gramme pheno-
thiazine, six of these being enclosed in each gelatine capsule. Each tablet also
contained some phenolphthalein and also some tartaric acid and sodium bicar-
bonate, the two latter ingredients being included to ensure the breakdown of
the tablet in the stomach.
On 10-11-39 the Marked lamb, weighing 74 lb., was given four capsules
containing a total dose of 24 grammes of phenothiazine (about 0 . 3 gramme
per lb. body weight). On the same date the Unmarked lamb, weighing 89 lb.,
was also given a total dose of 24 grammes in four gelatine capsules (about 0. 27
gramme per lb. body weight).
The effect of these doses on these two lambs was, in both cases, immediate.
The day after the dose, the egg count of the Marked Lamb had dropped from a
mean of 7,400 to a mean of 1,700. Three days after the dose the mean egg
count was 200 e.p.g. and it remained at or near this figure until 56 days after
the dose. An attempt was then made to remove the remaining few worms,
which were producing a mean egg count at that time of about 200 e.p.g., by
giving on 5-1-40, 7 grammes phenothiazine in the form of the same tablets as
those that had been given before. This did not lower the egg count. On
10-1-40 a further six tablets (6 grammes) were given, but the egg count was
still not appreciably affected. On 18-1-40 and 19-1-40, 12 and 13 days respec-
tively after the second dose, successive doses of 6 grammes of the same tablets
were given and the egg count dropped to a mean of 100 e.p.g. Successive
doses of 6 grammes of the same tablets were repeated on 25-1-40 and 26-1-40
and the egg count was negative for the next three days, showing a mean of 100
e.p.g. again on the fourth day. Three successive daily doses of 6 grammes of
the same tablets were then given on 31-1-40, 1-2-40 and 2-2-40 but, with the
256
Anthelmintic Action of Phenothiazine
contortus, half of which may be females each producing 5,000 eggs per 24
hours, a 90 per cent. reduction of the worm burden still leaves 800 worms, 400
of which can be calculated as being females, so that this sheep will still be
voiding 2,000,000 eggs in 24 hours—a considerable daily infestation of the
pasture if it is multiplied by a number of sheep in a flock.
2.—EXPERIMENTS ON FLOCKS IN THE FIELD
A. Examination of two lambs sent in to the Institute from a farm in
Norfolk showed that one contained 3,600 Ostertagia in the abomasum and 6,400
Nematodirus in the intestine, and the other 35,000 Ostertagia in the abomasum
and no worms in the small intestine. This flock was regarded as suitable for
dosing and experiments.
The owner agreed that 50 animals (ewes and lambs) should be dosed with
phenothiazine and 50 with copper sulphate (without nicotine) to compare the
effects of these two anthelmintics, the remainder of the flock being dosed with
copper sulphate without nicotine. The two lots of 50 ewes and lambs (Groups
1 and 2) were all marked by clipping the ears and each animal was weighed
separately on a weighbridge before the dose was given. A faecal sample was
taken from the rectum of each animal when the dose was given and these
samples were mixed to provide composite samples for each of the two groups.
Each of the lambs and ewes in Group 1 was given 5 grammes of phenothiazine
in tablet form and each in Group 2 was given 2 oz. of a 1 per cent, solution of
copper sulphate without nicotine. On the 10th, 20th and 30th days after the
dose each lamb was again weighed on the same weighbridge and a faecal
sample was taken from the rectum of each to provide a composite egg count
for each of the two groups. The average weight of Group 1 was 53. 8 lb. and
that of Group 2 54.8 lb.
For the first 20 days the animals were folded on sainfoin and during the
first ten days only they all received extra corn rations. For the final ten days
they were moved from the sainfoin to tares, the sainfoin having become by then
so much woodier in the hot, dry weather that the farmer considered this change
advisable.
The following tables show the individual weights of the lambs, the total
weights of each group and the egg counts on the composite faecal samples from
each group.
TABLE I
Group 1. Nos. 1-50. Weights stated in lb. Avoirdupois
No.
1
2
Initial Weight
24-5-40 Before
Dose of 5 Grammes
Phenothiazine
57
48
Weight
3-6-40
68
56
Weight
13-6-40
71
64
Weight
24-6-40
79
67
GEOFFREY
LAPAGE
257
No.
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Initial Weight
24-5-40 Before
Dose of 5 Grammes
Phenothiazine
52
*53
64
65
63
31
*60
49
60
57
*53
68
48
67
*46
46
40
(22)
58
27
*48
52
66
*57
(32)
64
53
63
63
73
73
54
*57
58
63
55
45
59
48
60
55
45
51
55
47
55
50
58
Weight
3-6-40
60
57
70
74
74
34
67
56
66
68
64
76
56
76
58
54
46
24
71
36
58
60
76
64
37
68
60
69
70
82
81
64
68
63
76
60
53
66
56
70
64
58
58
62
57
68
60
68
Weight
13-6-40
70
62
65
73
80
38
69
62
72
69
71
82
60
83
62
60
53
22
74
40
64
66
84
72
38
74
65
74
73
90
84
72
75
72
82
66
58
72
60
74
70
66
64
64
56
73
66
64
Weight
24-6-40
82
71
85
86
86
46
77
65
80
79
81
90
65
88
70
66
58
22
77
47
71
71
87
82
44
76
69
77
80
94
85
77
69
82
87
71
61
76
64
82
74
73
71
70
70
79
70
73
258
Anthelmintic Action of Phenothiazine
Group 2. Nos. 51-100. Weights stated in lb. Avoirdupois
No.
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
Initial Weight
Before Dose of
2 oz. of 1 per cent.
Copper Sulphate
58
77
57
53
51
50
37
51
*53
42
63
70
53
22
50
66
76
50
13
*64
51
46
*45
53
49
50
66
57
53
58
54
63
30
60
60
*44
*50
*50
59
73
52
56
51
71
50
61
54
54
76
56
Weight
3-6-40
66
93
70
60
56
54
44
58
63
50
64
84
58
28
54
72
85
56
16
76
62
50
55
64
58
57
78
64
60
66
63
70
34
70
71
50
58
58
67
86
60
66
56
80
60
70
60
60
88
64
Weight
13-6-40
75
95
76
66
52
56
52
62
68
55
70
90
60
30
60
79
92
66
18
78
65
57
63
76
63
62
85
73
61
64
66
80
38
70
78
59
66
65
64
90
67
73
64
90
68
76
60
64
96
68
Weight
24-6-40
82
100
85
75
54
64
58
65
76
65
77
91
70
36
64
84
101
73
20
89
72
61
70
82
65
66
90
78
64
70
76
87
40
74
89
68
72
71
80
96
73
82
67
92
76
87
63
64
100
73
GEOFFREY
LAPAGE
259
TABLE II
Total weights in lb. Avoirdupois
24-5-40
3-6-40
13-6-40
24-6-40
Group 1. Nos. 1-50.
Given 5 Grammes Phenothiazine.
Total Weight.
2,693
3,107
3,440
3,642
Increase.
414
Average 8 .3
333
Average 6.6
302
Average 6.04
Eggs per Gramme
Average of 2
Counts.
1,050
150
50
100
Group 2. Nos. 51-100.
Given 2 oz. of 1 per cent. Copper Sulphate.
Total Weight.
2,708
3,012
3,369
3,677
Increase.
304
Average 6.08
357
Average 7.1
308
Average 6.1
Eggs per Gramme
Average of 2
Counts.
2,150
400
3C0
250
It will be seen that the weight increases of individual lambs differed con-
siderably, and that some of the animals at times lost a few pounds in the inter-
vals of ten days. The main fact emerging from the experiment is that there
was no significant difference in the progress of the weight increase in the two
groups. The slight advantage on the 20th day in favour of the group given
copper sulphate and its disappearance by the 30th day should be noted here,
in view of the results of the next two experiments. It could be argued that the
dose of phenothiazine that was given was small, a normal therapeutic dose
being 10 to 30 grammes. Yet the egg count of Group 1 was reduced by this
small dose in about the same proportion as the reduction of the higher egg
count of Group 2 by copper sulphate. It could equally well be argued that, in
spite of the higher egg count of Group 2, about twice as high as that of Group 1,
the copper sulphate enabled this group to maintain a weight increase equiva-
lent to that of Group 1 given a small dose of phenothiazine. The experiment
does not tell us whether, if the dose of phenothiazine had been higher, Group
1 would have shown a markedly greater increase of weight than that attained by
Group 2. Another experiment, now in progress, may help to answer this
question. Meanwhile, this experiment shows that even 5 grammes of pheno-
thiazine has a significant effect on a comparatively heavy infestation with
Haemonchus, Ostertagia and Nematodirus.
It has been suggested [Singer and Baker. (1940.) Cornell Vet. 30. 375-382
and others] that Nematodirus is one of the nematodes (Trichuris and Ancylos-
toma deudenale may be others) which are comparatively little affected by pheno-
thiazine, but the writer has as yet seen no evidence in favour of this view.
B. Experiment A was repeated on a group of ewes and lambs belonging to
this Institute, but the egg counts on the composite faecal samples taken before
dosing were low, so that little information was expected from this experiment
about the relative efficiencies of phenothiazine and copper sulphate. Further,
accidental obliteration of some of the markings prevented the keeping of an
accurate record of the weight of individual animals. The two groups A and B
were kept separate, grazing on different fields about a mile apart.
The following table (see next page) gives the relevant data about these
animals. It shows that the weight increase during the 23 days following the
260
Anthelmintic Action of Phenothiazine
dose was small. Some animals, like some of those in experiment A, lost a few
pounds. Both copper sulphate and phenothiazine reduced the egg count of
the ewes to 0, while the egg counts of the lambs were not appreciably affected
by either anthelmintic.
It will be seen that in this experiment, unsatisfactory though it was, there
was, 23 days after the dose, a slight advantage in weight increase in favour of
the group given copper sulphate. In experiment A there was a similar advant-
age, 20 days after the dose, in favour of the group given copper sulphate. By
the 30th day this had disappeared. In the experiment next to be described,
the group given phenothiazine attained, by the 30th day, a total weight
approaching twice that attained by the group given copper sulphate and
nicotine.
C. One hundred lambs, three to four months old, were included in this
experiment. On 5-7-40 one lamb of this flock had been sent to the Institute
for post-mortem examination. A worm count done on it showed 2,100 Oster-
tagia in the abomasum and 50,000 or more Nematodirus in the small intestine.
Egg counts on the contents of the colon and rectum showed 13,800 eggs of
Nematodirus per gramme and 3,500 eggs per gramme of other nematodes,
presumably Ostertagia.
TABLE III
Ewes
Lambs
Ewes
Lambs
Total Weight
Before Dose
on 27-5-40.
Composite Egg Count
Before Dose on
27-5-40.
Total Weight on
20-6-40
(23 days later).
Composite Egg Count
on 20-6-40
(23 days later).
Total
Gain.
Growp A. Given Copper Sulphate (10 to 15 c.c. of 5 per cent. solution according to body weight)
2,092 lb.
875 „
350 e.p.g.
50 „
2,186 lb.
1,033 „
0 e.p.g.
150 „
94 lb.
Average 1.9
158 lb.
Average 3.1
Group B. Given Phenothiazine Tablets (in the proportion of about 0.1 gramme per lb. body weight).
2,033 lb.
686 „
850e.p.g.
450 „
2,094 lb.
821 „
0 e.p.g.
500 „
81 lb.
Average 1.6
135 lb.
Average 2.7
On 26-6-40 the 100 lambs were divided into Groups 1 and 2 of 50 lambs
each. Each lamb of Group 1 was given 5 grammes of phenothiazine in tablet
form (cf. experiment A) ; each lamb of Group 2 was given 5 to 8 c.c. (according
to the size of the lamb) of a solution containing 10 per cent. of copper sulphate
and 10 per cent. of a solution containing 40 per cent. of nicotine sulphate.
McEwen has informed the writer that he gave for his experiments reported
elsewhere in this symposium, 20 c.c. of a solution containing 5 per cent. of
copper sulphate and 5 per cent. of a solution containing 40 per cent. nicotine
alkaloid. His dose of copper sulphate and nicotine was thus rather more than
that given to the lambs used in this experiment. McEwen, however, gave
much larger doses of phenothiazine in his experiments, giving 30 grammes to
each lamb in his experiment 1 and 10 grammes to each in his experiments 2
and 3.
Faecal samples were taken with the finger from the rectum of each lamb
before it was dosed.
The total weight of each group of lambs was ascertained by weighing the
lambs on a weighbridge. It was discovered that the weighbridge recorded a
GEOFFREY
LAPAGE
261
difference of 4 to 6 lb. in the weight of each animal according to whether it
stood at one or other end of the platform of the machine, while an intermediate
weight was recorded when it stood in the middle of the platform. This
possible error was reduced to a possible error of 2 lb. or so per lamb by inducing
each lamb to stand at the same end of the platform while its weight was being
recorded. This experience showed that it is possible to introduce a consider-
able error into any experiment involving the use of a weighbridge, unless the
position of the animal on the platform of the machine is always the same.
Another possible source of error in the weights is the normal variation in the
weight of each animal before or after a feed or access to water ; they should
always be weighed at the same time in the day. Further, when faecal samples
are being taken from each lamb, it is inevitable that different amounts of faeces
will be taken from each, either because the finger cannot take equal amounts
from each, or because the second 50 lambs in a group of 100 will have been
waiting longer and will often have emptied the rectum before the sample is
taken or because the faeces of some are looser than those of others, so that the
finger removes less and there are relatively fewer eggs in the amount of solid
removed. When, therefore, all the samples are mixed to form a composite
sample on which an egg count is made, it may occur that the egg count is really
done mostly on the faeces of the first 50 of the group and mostly on the best-
formed faeces of these. It may therefore not represent the average egg content
of the faeces of individual lambs.
On the 10th, 20th and 30th days after the doses were given, the lambs
were again weighed and faecal samples were taken. Throughout the experi-
ment the lambs were grazing on grass with the rest of the flock and had no
extra feed. The following table gives the relevant facts about them.
TABLE IV
26-6-40
5-7-40
15-5-40
26-5-40
Group 1.
Given 5 Grammes Phenothiazine in Tablet Form.
Total Weight.
2,898
(before the
dose)
3,367
3,200
4,208
Increase.
469
Average 9.38
Loss
167
Average 3.3
Increase
1,008
Average 20.16
Total gain in
30 days 1,310.
Average 26.2
Eggs per Gramme
Average of 2
Counts.
650
200
200
350
Group 2.
Given 5 to 8 c.c. of a Solution Containing 10 per
cent, of CuSO 4 and 10 per cent. of a Solution Con-
taining 40 per cent. Nicotine Sulphate.
Total Weight.
3,162
3,837
3,464
3,980
Increase.
675
Average 13.5
Loss
373
Average 7.46
Increase
516
Average 10.3
Total gain in
30 days 818.
Average 16.3
Eggs per Gramme
Average per 2
Counts.
400
550
400
400
No satisfactory explanation was found of the considerable loss of weight
during the second ten days in both groups but especially in Group 2. It may
GEOFFREY
LAPAGE
263
Attempts to Kill the Ciliates in the Rumen of Sheep with Phenothiazine
On 22-4-40 counts were begun of the ciliates in the rumen of a sheep with a
fistula into the rumen. The fistula had been made by Mr. Phillipson, of this
Institute, some weeks previously and the sheep was in good bodily condition,
weighing 258 lb.
The number of ciliates present was estimated only roughly because it was
difficult to count organisms so active as these. The method was to withdraw
2 c.c. of rumen contents, mix it with 98 c.c. water and remove 0.1 c.c. with a
pipette. This was diluted with an equal quantity of Lugol's iodine, which
killed the ciliates. The ciliates were then counted with the aid of an eye-piece
in which hairs crossed at right angles were fixed to divide the field into four
parts. The number counted was multiplied by 500 to give the number of cili-
ates per c.c. After the dose of phenothiazine, the ciliates already dead were
first counted in the drop. The iodine was then added to kill the rest, and the
number of ciliates was counted again, so that the number alive and presumably
not affected by phenothiazine could be estimated. Egg counts were also done,
but not more than an average of 50 e.p.g. were found so that the anthelmintic
effect of the phenothiazine was ignored.
The daily ciliate counts were :—
22-4-40
23-4-40
24-4-40
25-4-40
26-4-40
576,266
484,132
1,463,066
543,000
448,000
27-4-40
28-4-40
29-4-40
30-4-40
570,000
Not done
1,013,000
574,500
On 30-4-40 four gelatine capsules, containing six tablets each containing
1 gramme of phenothiazine—a total dose of 24 grammes of phenothiazine—
were placed in the rumen through the fistula opening. The sheep thus received
a dose of about 0.09 gramme per lb. body weight. Six hours later it was
passing red urine. The gelatine of a capsule put into rumen contents in a
flask on the previous day and incubated at 38° C. was dissolved in half an hour,
and the phenothiazine was set free. It was therefore reasonable to assume that
five and a half hours after the phenothiazine became free in the rumen the
animal was passing thionol in the urine.
Ciliates were counted in samples of rumen contents taken one, four and
twelve hours respectively after the capsules were administered, but no appre-
ciable decrease in the living ciliates was noted. No toxic effects whatsoever
were observed in this sheep. The conclusion was therefore that a dose of
0.09 gramme of phenothiazine per lb. body weight directly introduced into the
rumen through a fistula did not have any appreciable effect on the ciliates of
the rumen.
CALVES
Only one series of calves has been treated. All the calves were about six
months old, but their egg counts were not high. They were all dosed at the
farm, no change being made in the conditions under which they were kept
there. They were all given the first phenothiazine dispersion issued by Impe-
rial Chemical Industries. The table (overleaf) shows the results, and it will be
264
Anthelmintic Action of Phenothiazine
seen that the egg counts of all those which were dosed except No. 6, were reduc-
ed by the dose to 0, but the egg counts of the controls were also very low, so
that this result is inconclusive. The results obtained with the marked and
unmarked lamb (recorded above) show that it is unlikely that the egg count
reduced to 0 would have continued at 0 for very long and that it would probably
have been very difficult to keep the egg count at 0. It is likely that 50 to 200
e.p.g. would have remained even after repeated doses. The chief value of this
experiment was that it showed that no toxic effects were observed in calves
six months old when doses of 80 to 125 grammes of phenothiazine were given.
TABLE V.
Date.
20-10-39
21-10-39
22-10-39
23-10-39
24-10-39
25-10-39
26-10-39
27-10-39
28-10-39
29-10-39
30-10-39
31-10-39
1-11-39
2-11-39
6-11-39
Kept in a barn.
No.l.
500
600
Given
100 grammes
Phenothiazine
100
0
0
0
No. 4.
Contr.
No faeces
100
200
50
100
0
Kept Outside in a Compound on Straw.
No. 5.
300
0
Given
125 grammes
Phenothiazine
100
50
0
0
No. 6.
200
150
Given
100 grammes
Phenothiazine
No faeces
250
100
50
No. 7.
100
100
Given
80 grammes
Phenothiazine
100
0
0
0
No. 8
Contr.
400
200
200
50
100
100
No. 9.
Contr.
200
200
0
200
0
50
No. 10.
Contr.
100
500
500
150
400
400
HORSES
PONIES DRENCHED WITH PHENOTHIAZINE.—Three Shetland ponies and
one New Forest pony were offered for experiment by Dr. Hammond of the
University of Cambridge School of Agriculture. All these animals were grazing
and were kept in the field during the experiment. They ranged in age from
three to five years, but the weight of only one was ascertainable at 664 lb.
Two were kept as controls and two were given 80 grammes and 60 grammes
respectively of the first phenothiazine dispersion issued by Imperial Chemical
Industries. This corresponded to a dose of about. 0.1 gramme per lb. body
weight. No toxic effects were observed, but the day after the dose red urine
was passed and the mucosae of the eyes, nose and mouth took on a bronze
coloration which gradually waned until it had disappeared four to five days
after the dose. It was no doubt due to thionol in the blood.