NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
N-BUTYLIDENE CHLORIDE
179
Schlingman's tests, therefore, throw no light on the efficacy of tetrachlorethylene
for nematode parasites of the horse. Raffensperger, in a paper as yet unpublished,
has reported on critical tests of tetrachlorethylene alone and in mixtures with oil of
chenopodium for parasites of the horse.
EXPERIMENTAL PROCEDURE.
With the exception of the first experiment reported in this paper, where visual
examination of the feces was made after treatment, the method employed was that
developed by Hall and commonly used in all anthelmintic work carried out in the
Zoological Division. This method consists of screening all feces passed after the
administration of the anthelmintic in order to recover all parasites removed by the
treatment, the slaughter of the animal after a suitable number of days, and the
screening of the contents of the digestive tract to recover worms not removed by the
treatment.
RESULTS OF EXPERIMENTS.
EXPERIMENT 1.
Horse No. 1, an 8-months-old colt weighing 282 kgm. (620 pounds) was fasted
24 hours and dosed by stomach tube with 0.21 c.c. of n-butylidene chloride per
kilogram of weight, a total of 60 c.c, in 480 c.c. of raw linseed oil. There was no
reaction to the treatment. The animal passed the following parasites :—
—
First day . . . . .
Second day . . . . .
Third day . . . . .
Fourth day . . . . .
Fifth day . . . . .
Sixth day . . . . .
Total .
Number and kind of worms passed.
2 immature ascarids, 19 cylicostomes, 1 oxyurid.
2 cylicostomes, 1 bot.
7 immature ascarids, 1,566 cylicostomes. I oxyurid.
2 immature ascarids, 208 cylicostomes, 4 Poieroatomum ratzii.
1 immature ascarid, 24 cylicostomes, 2 P. ratzii, I bot.
None.
12 immature ascarids, 1,819 cylicostomes, 6 P. ratzii, 2 oxyu¬
rids, 2 bots.
The animal was killed 17 days after the administration of the anthelmintic.
No fecal examination for worms was made between the sixth and seventeenth days,
F
180 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ II, II
but presumably all worms removed by the anthelmintic would have been passed
by the sixth day. The following parasites were recovered post-mortem:—
Location.
Stomach
. . . . .
Small intestine
.
.
.
.
Caecum and large colon . . .
Small colon
.
.
.
.
.
Number and kind of worms found post-mortem.
266 Gastrophilus inteslinalis, 59 G. nasalis.
139 immature ascarids.
.13 Strongylus vulgaris, I immature ascarid, 1 Triodontophorus
intermedins, 13 T. lennicollis, 449 cylicostomes, hundreds*
of oxyurid larvæ, and large numbers* of Probstmayria
vivipara.
3 immature ascarids.
* Owing to the very small size of these worms and the large quantity of fecal material, detailed
counting would have involved an unwarranted expenditure of time, especially in view of the apparent
low efficiency of the drug against these species.
A large ulcer in the wall of the large colon contained 7 Triodonlophorus tenui¬
collis, There were 30 larvae of Strongylus vulgaris in different stages of develop-
ment in a large aneurism of the anterior mesenteric artery.
If the 1 immature ascarid in the caecum and the 3 in the small colon are con-
sidered as having been removed by the anthelmintic, the treatment was 11 per cent.
effective against ascarids and 0 per cent. effective against strongyles, Triodonto¬
phorus spp., and Probstmayria vivipara. The anthelmintic removed 80.2 per cent.
of the cylicostomes, less than 1 per cent. of the oxyurids, and 1 per cent. of the
bots. However, as all the ascarids found in the animal were immature and the
colt was not killed until 17 days after the administration of the anthelmintic, it can-
not be safely assumed that the drug removed only 11 per cent. of the ascarids, since
some or many of those remaining may have reached the intestinal tract after the
treatment was given. The same may be said for Strongylus vulgaris. Therefore,
this particular test failed to give accurate information as to the value of n-buty¬
lidene chloride against ascarids and strongyles.
Schlingman (11) has shown that the administration of fats and oils reduces
the efficacy of tetrachlorethylene for dogs, and Hall (5) found that oil reduced
the efficacy of carbon tetrachloride, a fact in keeping with the findings of Lamson,
Robbins, and Ward (6) and Robbins (9) that the rate of absorption of carbon
tetrachloride and tetrachlorethylene is greatly increased in the presence of fats and
oils. It was thought that these results might apply to other chlorinated hydrocar-
bons and that therefore the simultaneous administration of n-butylidene chloride
with raw linseed oil increased the absorption and reduced the anthelmintic efficacy
N-BUTYLIDENE CHLORIDE
181
of the drug. For this reason, in the remaining experiments in which oils were used
they were given five hours after the administration of the n-butylidene chloride.
EXPERIMENT 2.
Horse No. 2, a 22-years-old gelding weighing 484 kgm. (1,060 pounds), was
fasted 24 hours and dosed by stomach tube with 0.207 c.c. of n-butylidene chloride
per kilogram of weight, a total of 100 c.c., followed in five hours by 960 c.c. of raw
linseed oil. There was no reaction to the treatment; the animal refused feed the
day after treatment, but the second day consumed the usual quantity. The follow-
ing parasites were passed :—
—
First day .
.
.
.
.
.
Second
day.
.
.
.
.
.
Third and Fourth days . . {
Fifth day
.
.
.
.
.
.
Sixth day
.
.
.
.
.
.
Total
.
Number and kind of worms passed.
18 cylicostomes.
175 cylicostomes.
374 cylicostomes, 10 Strongylus edentatus, 5 Triodontophorus
tenuicollis.
2 Poleriostomum ratzii, 12 Craterostomum spp.
5 S. edentatus. 5 cylicostomes.
None.
572 cylicostomes, 15 S. edentatus, 5 T, tenuicollis, 2 P.
ratzii, 12 Crateroslomum spp.
The animal was killed 15 days after the administration of the treatment, and
the following parasites were recovered post-mortem ;—
Location.
Stomach . . . . . .
Rectum. . . . . .
Caecum.
.
.
.
.
.
Number and kind of worms found post-mortem.
25 Gaslrophilus intestinalis, 81 G. nasalis.
1 G. hemorrhoidalis.
1 Strongylus vulgaris.
Each of two abscesses in the wall of the double colon contained one Strongylus
vulgaris. An aneurism was found in the anterior mesenteric artery, but it contained
no strongyle larvae. The treatment was 100 per cent. effective against cylicostomes,
S. edentatus, Poteristomum ratzii, Triodontophorus tenuicollis and Craterostomum
spp. It failed to remove the one specimen of S. vulgaris, which, however, might
have entered the intestinal tract after the administration of the treatment, as the
F 2
182 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ II, II
horse was not killed until 15 days after treatment. The treatment was entirely
ineffective for the removal of bots.
EXPERIMENT 3.
Horse No. 3, a 2-year-old colt weighing 324 kgm. (712 pounds) was fasted 24
hours and dosed by stomach tube with 0.309 c. c. of n-butylidene chloride per
kilogram of weight, a total of 100 c. c., followed in five hours by 480 c. c. of raw
linseed oil, also given by stomach tube. There was no reaction to the treatment.
The following parasites were passed:—
—
First day . . . . . .
Second day. . . . . .
Third day. . . . . .
Fourth, day. . . . . .
Fifth day . . . . . .
Total .
Number and kind of worms passed.
294 cylicostomes, 1 oxyurid, 1 bot.
106 cylicostomes, 1 Strongylus sp.,* 2 Oxyurids, 2 bots.
78 cylicostomes, 3 Poteriostomum imparidentatum, 1
Crateroslomum sp., 1 Oesophagodontus robustus.
19 cylicostomes.
None.
497 cylicostomes, 1 Strongylus sp., 3 Oxyurids, 3 bots,
3 P. imparidentatum, 1 Crateroslomum sp. and 1
O. rooustus.
*Specific identification was not possible because of maceration.
The animal was killed on the seventh day after treatment and the following
parasites were collected post-mortem:—
Location.
Stomach
.
.
.
.
.
.
Small intestine. . . . .
Caecum
.
.
.
.
.
.
Double colon . . . . . .
Number and kind of worms found post-mortem.
Large number of Castrophlus intestinalis and G. nasalis
present but not counted.
None.
2 cylicostomes, 12 Strongylus vulgaris, 1 S. edentatus.
10 cylicostomes, 1 Poterioslomum imparidentatum, 4 oxyurids.
The efficacy of the treatment was as. follows: 97 per cent. for cylicostomes, 7
per cent. for Strongylus spp., 75 per cent. for Poterioslomum imparidentatum, 100
per cent. for Oesophagodontus robustus, 43 per cent. for oxyurids, and probably less
than 1 per cent. for bots.
In an aneurism in the anterior mesenteric artery there were several agamic
specimens of Strongylus vulgaris. Here again, it was not possible to determine
whether specimens of S. vulgaris unaffected by the anthelmintic entered the caecum
N-BUTYLIDENE CHLORIDE
183
after the administration of the drug and were found there post-mortem, although
in view of the number found it would be reasonable to assume that at least some of
these worms were present as adult forms in the large intestine at the time of
treatment.
EXPERIMENT 4.
Mule No. 430, a female about 18 years of age, weighing 295 kgm. (649 pounds),
was fasted 36 hours and dosed by stomach tube with 0.3 c.c. of n-butylidene
chloride per kilogram of weight, a total of 88.5 c.c. followed in five hours by 180 c.c.
of castor oil in 540 c.c. of liquid petrolatum, also given by stomach tube. The
animal did not consume all the feed the next day, but on the second day after
treatment it ate normally and continued to do so thereafter. The following
parasites were passed:—
—
First day
Second day
.
Third day
.
Fourth day
.
Fifth day
.
Number and kind of worms passed.
None.
1 Poteriostomum ratzii, 636 cylicostomes, 1 Strongylus
equinus.
1 P. ratzii, 966 cylicoatomes, 4 S. vulgaris, 2 S. equinus,
2 S. edeniatus.
1 P. ratzii, 220 cylicostomes, 1 S. vulgaris, 1 S. edentatus.
3 P. ratzii, 80 cylicostomes.
The animal was killed on the fifth day after treatment; The following
parasites were collected from the small colon and must be regarded as having
been passed out and therefore credited as removed by the anthelmintic : 12
Poteriostomum ratzii, 72 cylicostomes, 1 Strongylus vulgaris, and 1 S. edentatus.
Total worms passed: 18 Poteriostomum ratzii, 1,974 cylicostomes, 6 Strongylus
vulgaris, 3 S. equinus and 4 S. edentatus. The following parasites found post-
mortem were not affected by the anthelmintic:—
Location.
Stomach . . . . . .
Small intestine .
.
.
.
.
Caecum
.
.
.
.
.
.
Large colon . . . . . .
Number and kind of worms found post-mortem.
22 Gastrophilus intestinalis, 7 G. nasalis.
7 G. nasalis.
1 Strongylus vulgaris.
29 Poteriostomum spp.
7,086 cylicostomes, 3 S. vulgaris, 3 S. equinus, 5 S. edentatus
1 oxyurid larva.
The effieacy of the treatment was as follows: 37 per cent. for Poteriostomum
spp., 21.8 per cent. for cylicostomes, 60 per cent. for Strongylus vulgaris, 50 per
cent. for S. equinus, 44.4 per cent. for S. edentatus (or 52 per cent. for all Strongylus
184 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDBY [ II, II
spp.), 0 per cent. for oxyurids, and 0 per cent. for bots. One S. vulgaris found in
the large colon was embedded in the wall of that organ, the head end projecting for
a distance of 6 mm. above the mucosa. Obviously no anthelmintic could have
removed this specimen. An aneurism in the anterior branch of the anterior
mesenteric artery contained 3 larvae of S. vulgaris and a second aneurism in the
right branch of the anterior mesenteric artery contained 15 larvae of S. vulgaris.
In the animals used in the first three experiments, n-butylidene chloride failed
completely to remove any specimens of Strongylus vulgaris, but in the present
experiment the drug removed a larger percentage of this species than of any other.
This fact indicates that S. vulgaris is not necessarily resistant to the action of
n-butylidene chloride, although it might be inferred from the three previous
experiments that it is. Apparently the drug will remove a majority of these forms
when they exist as adults in the lumen of the intestinal tract at the time the
anthelmintic is administered.
The results against cylicostomes in the present experiment are at variance with
those obtained in the previous tests. The purgative in this test was different from
that used in the three previous ones, a fact which may have influenced the efficacy
of the n-butylidene chloride against cylicostomes. This point is more fully dis-
cussed later. It will be noted that the drug removed all these parasites from the
caecum but left a large number in the double colon. This circumstance suggests
that by the time it reached the double colon the drug was so diluted that it was not
present in sufficient concentration to act on the worms.
EXPERIMENT 5.
Horse No. 466, a 10-year-old mare weighing 459 kgm. (1,010 pounds), was
fasted 36 hours and dosed with 0.3 c.c. n-butylidene chloride per kilogram of
weight, a total of 137.7 c.c., administered in capsules followed immediately by
1 ounce of aloes in capsule. Several capsules containing n-butylidene chloride
were broken in the mouth, but the animal suffered no reaction from these
accidents. There was no reaction to the treatment. The following parasites were
passed:—
—
First day .
....
Second day
....
Third day
.
....
Fourth day
....
Fifth day
.
....
Number and kind of worms passed.
S cylicostomes.
332 cylicostomes.
1,496 cylicostomes, 1 oxyurid, 5 Strongylus edentatus.
800 cylicostomes, 1 S. vulgaris, 6 S. edentatus.
644 cylicostomes.
N-BUTYLIDENE CHLORIDE
185
The animal was killed on the fifth day after treatment; 640 cylicostomes were
recovered from the small colon and must be considered as having been removed by
the anthelmintic.
Total worms passed: 3.920 cylicostomes, 11 Strongylus edentatus, 1 S. vulgaris,
and 1 oxyurid. Parasites not affected by the anthelmintic were recovered post-
mortem, as follows:—
Location.
Stomach
Small intestine
.....
Caecum
......
Large colon
Number and kind of worms found post-mortem.
2 Gastrophilus nasalis, 2 G.intestinalis.
1 G. nasalis.
256 cylicostomes.
14,360 cylicostomes, 8 Strongylus edentatus, 12 Triodonto¬
phorus serratus, 2 Paterovstomum ratzii, 1 oxyurid.
The efficacy of the treatment was as follows: 100 per cent. for Strongylus
vulgaris, 57.9 per cent. for S. edentatus (or 60 per cent. for all Strongylus Spp.), 21.2
per cent. for cylicostomes, 0 per cent. for Poleriostomum ratzii, 50 per cent. for
oxyurids, 0 per cent. for Triodontophorus serratus, and 0 per cent. for bots.
Aloes did not prove to be an advantageous purgative, as it gave no better
supplementary action to the anthelmintic than did the. castor-oil liquid-petrolatum
mixture used in the previous experiment. As in the previous experiment, the
anthelmintic removed most of the cylicostomes from the caecum but apparently
failed to reach those in the colon. The large number of cylicostomes recovered
from this animal is remarkable.
EXPERIMENT 6.
Horse No. 4, an aged mare weighing 432 kgm. (950 pounds), was fasted 30
hours and dosed by stomach tube with 0.317 c.c. of n-butylidene chloride per
kilogram of weight, a total of 137 c.c. followed in five hours by 960 c.c. of raw
linseed oil. There was no immediate reaction to the treatment, but one hour later
the mare was sweating profusely and persisted in lying down. The pulse was 62
and the respiration 40 per minute. Two hours after the treatment the mare had
186 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ II, II
returned to normal, the pulse being 40 and the respiration 10. The following
parasites were passed:—
—
First day . . . . . .
Second day
.
.
.
.
.
Third day . . . . . .
Fourth day . . . . .
Fifth and sixth days . . . .
Seventh day . . . . .
Total .
Number and kind of worms passed.
356 cylicostomes, 1 bot.
280 cylicostomes.
235 cylicostomes, 1 Strongylus edentatus, 1 Poteriostomum
ralzii, 3 bots.
3 cylicostomes, 2 bots.
None,
1 bot.
874 cylicostomes, 1 S. edentatus, 1 P. ratzii, 7 bots.
The mare was killed 11 days after treatment, and the following parasites were
recovered post-mortem:—
Location.
Stomach . . . . . .
Caecum
.
.
.
.
.
.
Colon
.
.
.
.
.
.
Number and kind of worms found post-mortem.
8 Gastrophilus intestinlis.
1 Strongylus vulgaris.
None.
The efficacy of the treatment was as follows:—100 per cent. for cylicostomes, 100
per cent. for Strongylus edentatus, 0 per cent. for S. vulgaris (or 50 per cent. for all
Strongylus spp.), 100 per cent. for Poteriostomum ratzii, and 46.7 per cent. for bots.
The fact that the animal was not killed until 11 days after treatment suggests
the possibility that the one Strongylus vulgaris found post-mortem entered the
lumen of the gut subsequent to the administration of the anthelmintic and that the
drug should not be charged with the failure to remove this parasite.
EXPERIMENT 7.
Horse No. 5, an aged gelding weighing 459 kgm. (990 pounds), was not fasted
before dosing and was given 0.333 c.c. of n-butylidene chloride per kilogram of
weight, a total of 150 c.c. This was followed in five hours by 960 c.c. of raw linseed
oil. There was no reaction to the treatment. The following parasites were
passed:—
—
First day . . . . . .
Second day.
.
.
.
.
Third day
.
.
.
.
.
Fourth day.
.
.
.
.
Total .
Number and kind of worms passed.
874 cylicostomes, 2 Strongylus spp. *
71 cylicostomes, 4 S. edentatus.
4 cylicostomes, 2 S. edentatus.
None.
949 cylicostomes, 8 strongyles.
* Could not be specifically identified for the reason that the anterior part was missing in each instance.
N-BUTYLIDENE CHLORIDE
187
The animal was killed 9 days after treatment and the following worms reco-
vered post-mortem:
Location.
Stomach
.
.
.
.
.
.
Caeoum
.
.
.
.
.
Double Colon
.
.
.
.
.
Small colon and rectum . . .
Number and kind of worms found post-mortem.
13 Gaslrophilus intestinalis.
None.
1 Triodontophorus tenuicollis.
None.
There were 3 larvae of Strongylus vulgaris in an aneurism of the anterior
mesenteric artery. Efficacy of the treatment: 100 per cent. for cylicostomes, 100
per cent. for Strongylus spp., 0 per cent. for Triodontophorus tenuicollis, and 0 per
cent. for bots.
EXPERIMENT 8.
Horse No. 452, a 12-year-old gelding weighing 482.7 kgm. (1,062 pounds), was
fasted 36 hours and given in capsules 0.3 c.c. of n-butylidene chloride per kilogram
of weight, a total of 144.8 c.c, followed in five hours by 960 c.c... of raw linseed oil
in a drench. There was no reaction to the treatment. The following parasites were
passed :—
—
First day .
.
.
.
. .
Second day . . . . .
Third day. . . . .
Fourth day. . . . .
Fifth
day.
.
.
.
.
Total .
Number and kind of worms passed.
No feces.
64 cylicostomes.*
548 cylicostomes, 4 Polerioslomum ralzii.
32 cylicostomes.
No feces.
644 cylicostomes, 4 P. ratzii.
* The feces on this day were dry and hard and an additional dose of 960 c.c. of raw linseed oil
was administered in the afternoon.
The animal was killed on the fifth day after dosing. The small colon contained
1 Poterioslomum ralzii and the large colon contained 1 Strongylus equinus dead and
much disintegrated with the head missing identification being made by the bursa ;
188 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ II, II
these parasites must be considered as having been removed by the anthelmintic.
No other parasites were found post-mortem. Efficacy of the treatment: 100 per
cent. for Strongylus spp., cylicostomes, and P. ratzii.
OTHER TESTS.
Dr. Robert Bardwell, Mereworth Stud, Lexington, Ky., offered to conduct
tests with n-butylidene chloride, and a quantity of the compound was forwarded to
him. The following is his report of one such test:—
We had a farm foal raised with the other foals which showed a few ascarids and
strongyle eggs on fecal examination. After starving her about 16 hours, I gave 50
c.c. The feces were examined for 48 hours but no worms found. The foal was
very constipated as a result of the drug and was slightly off feed, although nothing
serious was noted. Fecal examination one week after treatment was negative for
ascarids, positive for strongyles ; at two weeks fecal examination was negative for
both. The foal was autopsied but I could find no bots or worms of any kind. As
a result of this, I feel that this drug may be very useful.
In Dr. Bardwell's test, n-butylidene chloride apparently removed all ascarids
from the test animal, whereas in experiment 1, the drug given with raw linseed oil
apparently failed to remove many of the ascarids present. It is probable that
mixing raw linseed oil with n-butylidene chloride reduces the efficacy of the
anthelmintic against ascarids.
TESTS AGAINST HABRONEMA SPP.
Wright, Bozicevich, and Underwood (13), in reporting upon the use of carbon
disulphide as a treatment for equine habronemiasis, indicate that carbon disulphide
is a very effective treatment for the destruction of Habronema spp. and that the
efficacy of the drug is augmented when administration is preceded by gastric lavage
with a 2 per cent. solution of sodium bicarbonate. N-butylidene chloride was
tested on three animals infested with Habronema spp.
A gray gelding, about 15 years old and weighing approximately 1,200 pounds,
was dosed at 8.25 A.M. with 60 c.c. of n-butylidene chloride in capsules. The animal
appeared uneasy after the treatment and moved about considerably. At 9-15 A.M.
the horse was killed. Although the animal was said to have been fasted for 12
hours before treatment, the stomach was found to contain about 3 liters of feed.
The organ was immediately examined and the mucosa found to be slightly inflamed.
The odour of n-butylidene chloride was pronounced. One Habronema muscae was
found ; this specimen was alive.
N-BUTYLIDENE CHLORIDE
189
A roan mare, about 15 years old and weighing about 800 pounds, was dosed at
8-20 A.M. with 60 c.c. of n-butylidene chloride in capsules. There was no reaction to
the treatment. The mare was killed at 9-50 A.M. The mucosa of the stomach was
slightly inflamed. Nine Habronema muscae were found in the organ, 4 being alive
and 5 dead. The percentage of efficacy was therefore 55.5.
A black gelding, about 15 years old, and weighing about 1,100 pounds, was
dosed with 60 c.c. of n-butylidene chloride in capsules at 8-50 A.M. There was no
reaction to the treatment. The animal was killed at 11-10 A.M. Although the
animal was said to have been fasted for 12 hours before treatment, the stomach
was engorged with food. One hundred and nine Habronema microstoma were
recovered, of which 3 were alive and 106 dead. In this test, n-butylidene chloride
was 97.2 per cent. effective for the destruction of H. microstoma.
In the last test the interval of time between dosing and slaugther of the animal
was greater than in the two other tests, and it is possible that the additional time
gave the anthelmintic greater opportunity to act on the parasites present in the
stomach. It would appear from these tests that n-butylidene chloride is partially
effective against Habronema spp. ; no doubt the efficacy of the drug would be
materially increased if it were preceded by gastric lavage with an alkaline solution
as has been shown to be the case with carbon disulphide. It has been impossible
to determine this point because of the unavailability of suitable test animals.
DISCUSSION OF RESULTS.
In these tests, n-butylidene chloride administered in doses of 0.207 to 0.333 c.c.
per kilogram of body weight, followed in five hours by 960 c.c. (1 quart) of raw
linseed oil for a 1,000-pound animal (experiments 2, 6, 7 and 8), gave good results
against Strongylus spp., cylicostomes, and Poteriostomum spp. In experiment 2, the
drug removed 93.8 per cent. of all Strongylus spp., all of the cylicostomes, and all
Poteriostomum spp. In experiment 6, 50 per cent. of the Strongylus spp., all of the
cylicostomes, and all Poteriostomum spp., were removed. In experiment 7, all
Strongylus spp., and cylicostomes were removed. In experiment 8, all Strongylus
spp., cylicostomes, and P. ratzii were removed.
The administration of n-butylidene chloride in raw linseed oil in experiment 1
resulted in reduced efficacy for the anthelmintic, as none of the Strongylus spp.,
present were removed and only 80.2 per cent. of the cylicostomes. In experiment
3, in which the drug was followed in five hours by 480 c.c., of raw linseed oil for a
712-pound animal it is apparent that the dose of linseed oil was insufficient to
insure adequate purgation and possibly the reduced efficacy in this test is correlated
with the use of an inadequate amount of purgative.