NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
110
ANTI-TUBERCULOUS
COMPOUNDS
[ Vol. XXVI, Part III,
The synthetic medium employed for these trials had the following composi
tion :
I-Asparagin
Dipotassium phosphate
(K 2 HPO 4 .3H 2 O)
Sodium citrate
(Na 3 C 6 H 5 O 7 . 5 ½ H 2 O)
Magnesium sulphate
(Mg. SO 4 7H 2 O)
Ferric citrate scales
Dextrose
Glycerol C. P.
Distilled water
Reaction: PH7.
14.0 gm.
1.8 gm.
0.9 gm.
1.5 gm.
0.3 gm.
10.0 gm.
100.0 gm.
upto 1 litre
Sterilisation by autoclaving at 11 to 12 lb. for 25 minutes.
As all the compounds synthesised were sparingly soluble in water, they were
added to the medium in the form of suspensions obtained by triturating 50 mgm.
of each separately in 5 ml. quantities of 0.15 per cent aqueous agar solution and
sterilising in an autoclave at 10-11 lb. pressure for 25 minutes. 1 ml. of the suspension
was added, with sterile precautions, to 99 ml. of the synthetic medium contained
in each flask. Two sets of trials were put up in duplicate, one without agar
and the other with 0.15 per cent agar incorporated in the medium to render it more
viscous so as to increase its capacity for holding insoluble particles in suspension;
control flasks without drugs as also with known anti-tuberculous drugs, like INH,
were kept in each series for comparison.
The culture of Mycotuberculosis used for this trial was of the strain PN, a
human, virulent type maintained at this Institute for tuberculin preparation and
passaged occasionally through guinea-pigs for retaining virulence. Young (12
days' old) vigorously growing culture in the form of a thin surface pellicle on gly
cerine broth was used for seeding the experimental and control flasks. So far as
possible, uniformity in the size of inoculum in each flask was aimed at.
RESULTS
Comparative observations against drug-free controls were made at weekly
intervals for three weeks and the results are presented in Table I. It will be seen
that compounds No. 9, 13, and 18 compared favourably with p-amino-α-phenyl
pyridine and INH* in their in-vitro anti-tuberculous activity, while compound 1
tended to approach that limit.
*Isonex (Dumex) tablets of 50 mg. each were used for this trial.
112
ANTI-TUBERCULOUS
COMPOUNDS
[ Vol. XXVI, Part III,
TABLE I
Showing the in-vitro anti-tuberculous activity of the compounds
Lab.
Ref.
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Name of Chemical
4'—Aceto-4-aminodiphenyl
4'—Aceto-N-4-diphenylyl benzamidine
4'—Aceto-N-4-diphenylyl-O-tolylamidine
4'—Aceto-N-4-diphenylyl-m-tolylamidine
4'—Aceto-N-4-diphenylyl-p-tolylamidine
4'—Aceto-N-4-diphenylyl-3 : 4-xylylamidine
4'—Aceto-N-4-diphenylyl-p-anisoylamidine
4'—Propio-4-aminodiphenyl
4'—Propio-N-diphenylyl-o-tolylamidine
4'—Propio-N-4-diphenylyl-m-tolylamidine
4'—Propio-N-4-diphenylyl-p-tolylamidine
4'—Propio-N-4-diphenylyl-p-anisoylamidine
4'—Butyro-4-aminodiphenyl
4'—Butyro-N-4-diphenylyl-m-tolylamidine
4'—Butyro-N-4-diphenylyl-p-tolylamidine
4'—Butyro-N-4-diphenylyl-p-anisoylamidine
Ortho Cresotin hydrazide
Amount of growth (including inoculum) on the
8th day of
incubation
Agar
medium
+2
+2
+2½
+1½
+1½ +2½
+2½
+1½ +
+2
+1½
+3
+
+
+1½
+1½
+1½
Plain
medium
+
+2
+1½
+
+2½
+2½
+2
+2
+
+3
+3
+2
+
+1½
+1½
+2
+
15th day of
incubation
Agar
medium
+
+5
+5
+3
+3
+4
+4
+2
±
+3½
+4
+6
±
+
+3
+2
+2½
Plain
medium
±
+3
+2
+2
+3
+4
+3
+3
±
+6
+6
+3
±
+
+2
+
+
22nd day of
incubation
Agar
medium
+
+15
+15
+8
+14
+13
+13
+3
—
+14
+16
+15
—
+6
+12
+4
+7
Plain
medium
±
+4
+5
+4
+7
+15
+13
+8
—
+16
+16
+8
—
+6
+4
+
+
Remarks
Activity almost
approaching that
of INH
Similar to INH
Similar to INH
Substituted N'-benzylidene
derivatives of o-cresotin hydrazide (in the benzylidine residue)
18
19
20
21
o-OH
p-OMe
p-NMe2
Cinnamylidene
+
+1½
+1½
+
+
+1½
+2
+
+
+3
+3
+
±
+1½
+3
+
–
+10
+12
+2
–
+2
+12
+
Similar to INH
September, 1956 ] M. R. DHANDA et. al.
113
TABLE I—contd.
Showiug the in-vitro anti-tuberculous activity of the compounds
Lab.
Ref.
No.
Name of Chemical
Amount of growth (including inoculum) on the
8th day of
incubation
Agar
medium
Plain
medium
15th day of
incubation
Agar
medium
Plain
medium
22nd day of
incubation
Agar
medium
Plain
medium
Remarks
Substituted N'-bensylidene derivatives of o-cresotin hydrazide (in the benzylidine residue)
22
23
Piperonylidine
Meta Cresotin hydrazide
+
+
+
+
+2
+2
+1½
+1½
+12
+5
+6
+3
Substituted N'-benzylidene
derivatives
of m-cresotin
hydrazide
24
25
26
27
28
29
o-OH
p-OMe
p-NMe2
Cinnamylidene
Piperonylidene
Para Cresotin hydrazide
+2
+2
+2
+2
+
+1½
+
+2
+2
+2
+1½
+2
+3½
+4
+3
+4
+2½
+2½
+2
+4
+3
+4
+2½
+2½
+12
+11
+13
+15
+7½ +6
+5
+11
+11
+13
+7
+4
Substituted N'-benzylidene
derivatives
of p-cresotin
hydrazide
30
31
32
33
34
35
36
37
o-OH
p-OMe
p-NMe2
Cinnamylidene
Piperonylidine
p-amino-phenylpyridine
Isonicotin Hydrazide
Controls without drugs
+
+1½
+3
+1½ +2½
+
+
Not put up
+
+2
+2
+1½
+2½
+
+
+3
+2
+4
+7
+4
+7
± +
Not put up
+1½
+4
+4
+3
+5
± ±
+6
+5
+14
+16
+14
+20
—
—
Not put up
+4
+14
+13
+14
+13
—
—
+16
Notes : (1) Date of culturing—7-7-54 (observations made on the 15th, 22nd and 29th July, 1954).
(2) Numerals after the sign ' + ' indicate the extent of growth (e.g. +3½ is to be taken as +++± ).
(3) One plus in the first observation approximates to the size of the inoculum.
114
ANTI-TUBERCULOUS COMPOUNDS
[ Vol. XXVI, Part III,
TABLE II
Showing the results of viability tests after five weeks of incubation on 10 mg. per cent drug concentration
Description of flasks from which culture attempted
Compound No.
9
9
13
13
18
18
35
35
36
36
Control—Without drug
Control—Without drug
With or without agar
Without agar
With agar
Without agar
With agar
Without agar
With agar
Without agar
With agar
Without agar
With agar
Without agar
Without agar
Date of
subculture
on drug-
free medicum
12-8-54
do
do
do
do
do
do
do
do
Date of
observa-
tion
29-9-54
do
do
do
do
do
do
do
do
Growth observed
Profuse growth
Slight growth
No growth
do
do
do
do
Growth present
No growth
Remarks
Resembling control flasks.
About 3 sq. cm. in area
Inoculum still floating
do
do
do
do
About 12-15 sq.cm. in
area.
Inoculum floating.
Not available for subculture due to contamination
12-8-54
do
29-9-54
do
Profuse growth
do
September, 1956 ]
M.
R.
DHANDA
et. al.
115
TABLE III
Showing the in-vitro anti-tuberculous activity of compounds No. 1, 9,13, and 18 vis a vis INH and PAS at varyiug dilutions
Compound
No.
1
9
13
18
INH
PAS
Control
Date of
inoculation
8-12-54
Date of
observation
{18-12-54
28-12-54
{18-12-54
28-12-54
{18-12-54
28-12-54
{18-12-54
28-12-54
{18-12-54
28-12-54
{18-12-54
28-12-54
{18-12-54
28-12-54
Amount of growth at various drug concentrations
10 mg.
per cent
+
—
+
—
+
—
+
—
+
—
+
—
+++
+++
7.5 mg.
per cent
+
—
+
—
+
—
+
—
+
–
+
—
+++
+++
5 mg.
per cent
+
—
+
—
+
—
+
—
+
—
+
—
+++
+++
2.5 mg.
per cent
+
—
+
—
+
—
+
—
+
—
+
—
+++
+++
1.0 mg.
per cent
+1½
+
+
+
+
—
+
+
+
–
+
—
+++
+++
Remarks
} Comparable with INH and
PAS.
One + at first observation indicates almost the size of the inoculum.
116
ANTI-TUBERCULOUS
COMPOUNDS
[ Vol. XXVI, Part III,
SUMMARY
Thirty-four compounds have been tested in-vitro for their anti-tuberculous
activity, only four of which have shown promise; correlation of their liphophilic
nature and basicity with activity could not be established.
ACKNOWLEDGMENT
The authors are thankful to Dr V. S. Misra, Lecturer, Department of
Chemistry, Lucknow University for his keen interest in this work and to Shri B. R.
Sen Gupta for technical assistance.
REFERENCES
Buu Hoi et. al., (1952). Compt. rend. 235, 329 (Cited by Misra and Khare, 1954)
Hart, P. D'A. (1946). Brit. med. J. Dec. 7th 849.
Misra, V. S. and Khare, M. P. (1952). J. Indian chem. Soc. 29, 695
—(1953).
ibid. 30, 43
—(1954).
ibid. 31, 323
Rich, A. R. and Follis, R. H. (1938). Bull. Johns Hopkins Hosp. 62, 77
Robinson, R. (1940). J. chem. Soc. 1940, 505. (Cited by Misra and Khare, 1952)
LUMBAR PARALYSIS IN SHEEP AND GOATS
By RADHEY MOHAN SHARMA 1 and H. M. BHATIA 2
(Received for publication on April 5, 1955)
A N obscure disease has been occurring amongst sheep and goats at the Govern-
ment Livestock Farm, Hissar almost every year since 1944. It was, however,
observed for the first time in 1935 at the farm. The disease is of seasonal occurrence
and prevails from the beginning of September to the end of November or beginning
of December. All breeds of sheep, i.e. Bikaneri, Hissari and Lohi and all breeds of
goats, Betal, Hill, Desi and Angora maintained at the farm were found affected
irrespective of the age of the animal.
Symptoms
The symptoms observed in affected cases are : Staggering gait, inco-ordination
of movement of hind legs which are carried wide apart, weakness, lying down,
inability to stand and general dullness. The animal seems to be drunk and reels
to and fro. There is no appreciable rise of temperature. It may be subnormal
in advanced stages of the disease. The animal keeps on feeding even when lying
down, if hand fed. There is generally no irregularity of the bowels nor complete
loss of sensation of any part. The course of the disease is protracted and varies
from one to three weeks. In later stages the affected animal keeps on lying in a
very helpless condition and one generally thinks that it would die during the night
but it lingers on for a number of days.
Post-mortem lesions
Post-mortem lesions show engorgement of the blood vessels of brain, con-
gestion of the brain substance and spinal cord. The piameter shows pin point
haemorrhages. In chronic cases, both in sheep and goats, there is appreciable
inflammation of the abomasum and of the small intestines. Kidneys in some
cases show congestion. Heart, lungs and liver are usually normal.
Little is known about nervous diseases of sheep and goats. The literature on
this subject has been reviewed by Innes [1950]. Emoto [1923] reported paralysis
among goats in Japan which occurred from 1911 to 1924 amongst animals as im-
ported from Switzerland. He mentioned that the disease has been seen each year
in the late summer and autumn and that adult animals were usually affected. He
designated the condition as a non-purulent lymphocytic meningitis with cerebro-
spinal malacia. Crawford [1939-42] made observations on a disease of goats known
as "Lumbar Paralysis" which occurred in Ceylon amongst animals imported from
India or their progeny. He reported that there was motor weakness and posterior
inco-ordination and the onset of the disease was sometimes dramatically sudden;
there was no rise of temperature in affected cases and that the course of the disease
was either acute or subacute. He could neither transmit the disease by sub-cuta-
neous or intramuscular inoculation of brain and cord emulsions into healthy goats,
rabbits, guineapigs and mice, nor observe growth of any pathogenic organism on
cultural examination of blood, spinal cord and brain of the typical cases. Further
1 Govt. Livestock Farm, Hissar
2 Punjab College of Veterinary Science and Animal Husbandry, Hissar
117
12 AR/56
5
118
LUMBAR
PARALYSIS IN SHEEP AND GOATS [ Vol. XXVI, Part III,
work in Ceylon by Pillai, Mahmooth and Malkani [1950] confirmed Crawford's
findings and revealed that the disease affected a variety of Indian breeds imported
into Ceylon—Jamnapari, Sindhi, Kamoris, Alandi, Bengalori and in crosses between
these and local Ceylon goats. Gill [1931] reported the incidence of circling disease in
sheep in New Zealand due to Listerella Erysipelothrix monocytogenes. King
[1940] described an outbreak of listerellosis in goats in the U.S.A., as disseminated
encephalomyelitis with granulomatous lesions almost restricted to the brain stem,
the changes were regarded as a variety of myelin loss. Olafson [1940], Gifford and
Eveleth [1942] and Kaplan and Lager [1945] reported isolated cases of listerellosis
in the U.S.A. Annual reports of the Indian Veterinary Research Institute [1932-42]
show that Caprine Paralysis existed in India and that the disease could not be
successfully transmitted. The histopathological examination of cerebral cortex and
spinal cord showed meningeal congestion and haemorrhage, perivascular infiltra-
tions, neuronophagia, and destruction of nerve cells. The exact etiology of the
disease could not, however, be established. The possibility of the disease being due
to poisoning with Lathyrus sativus or some other fodder poisoning was excluded by
Crawford loc. cit by feeding experiments with a variety of plants. Streptococcal
infection was at one time considered to be the cause of the condition but later experi-
mental work did not support this view. Yamagiwa, Shoho, Tanaka et. al., [1941-47]
attributed this condition to injuries to the brain and spinal cord by immature
Setaria digitata and termed this condition as Setariosis. Innes, Shoho and Pillai
[1952] reported pathological studies on this condition and supported the Japanese
workers' viewpoint. Iyer and Seetharaman [1953] attributed cases of bovine
paraplegia in the Madras State as due to a deficiency of calcium and magnesium,
particularly the latter.
Investigation
The disease occurring amongst sheep and goats at this farm has been studied
from different aspects:
(1) Smears from blood, spleen, liver, kidneys, brain and spinal cord of the
affected cases on microscopical examination did not show the presence of any patho-
genic organisms or protozoan parasite. Materials from these organs and blood
sown on broth, plain agar, blood agar and Robertson's medium were also found to
be sterile.
(2) Several attempts were made from year to year to transmit the disease into
healthy sheep, goats and laboratory animals by injecting brain emulsion, spinal
fluid and blood by different routes but all failed. The Assistant Research Officer,
Disease Investigation Section, Indian Veterinary Research Institute, Izatnagar,
visited this farm in 1948 and conducted necessary trials to transmit the disease but
no conclusive results were achieved. He sent spinal fluid on ice in thermosflask to the
Research Officer, Disease Investigation Section, Indian Veterinary Research In-
stitute, per special messenger for transmission experiments but the disease could
not be reproduced.
120
LUMBAR PARALYSIS IN SHEEP AND GOATS [ Vol. XXVI, Part III,
(6) The possibility of the disease being due to Listerella infection was reasonably
excluded by subjecting serum samples from 11 recovered cases of the disease to
agglutination test for listerellosis at the Indian Veterinary Research Institute,
Mukteswar. Nine samples proved negative and two gave doubtful reaction when
tested with antigen prepared from Mukteswar stock Listerella culture.
(7) Attempts were made to grow the so called virus of the disease on chorio-
allantoic membrane of the developing chick embryo. The material was passed in
four passages. No satisfactory and uniform results could be achieved. There
were no lesions on the embryos after death. There was only congestion and
haemorrhage in some cases.
(8) In view of the fact that the disease could not be transmitted in spite of repea-
ted experiments, and that it appeared in the vaccinated animals, it is likely that the
disease in question is not of virus origin. The inability to demonstrate any bacteria
in blood, brain substance, and cerebrospinal fluid by microscopical, cultural and
serological tests excludes the possibility of a bacterial infection. Negative results
on chemical analysis of samples of fodder fed to these animals, and viscera from
affected cases point to the absence of any fodder or other poisoning.
In consideration of the above observations coupled with clinical symptoms shown
by the affected cases and findings of Johnson, Hamilton, Nevens and Boley [1948]
recording more or less similar condition in the calf due to thiamine deficiency, it
was suspected that the disease in question may be a vitaminosis B 1 . It was, therefore,
considered desirable to give a trial to thiamin administration. Sixteen cases of
the disease (11 caprine and 5 ovines) were divided into two groups with 8 animals in
each group. Animals in group No. 1 were treated with vitamin B 1 (Berin), a
preparation of Glaxo Laboratories (India) Ltd., by intramuscular route and by
mouth. Animals in group No. 2 were not given any treatment. Animals in both
the groups were kept in the hospital under identical conditions of feeding and
management. Seven animals (4 caprine and 3 ovine) got cured in group No. 1.
Out of the 7 cured cases, one goat had a relapse about one month after the treatment
and died. In group No. 2, 7 animals died and one recovered without any treatment.
The results are tabulated below :
Group of animals
1. Vitamin B 1 treated
2. Non-treated
No. of
animals
8
8
Cured
7*
1
Died
1
7
Percentage
recovery
87.5
12.5
*One goat out of seven cured cases had a relapse one month after the treatment and died.
The line of treatment consisted in the intramuscular administration of 1 c.c.
of Berin, 100 mg. each c.c. daily for the first 6 days followed by 1 c.c. of Berin
on alternate days during the second week. The animals were given orally
6 Berin tablets, 10 mg. each tablet on the days when no injections were given.
122
LUMBAR PARALYSIS IN SHEEP AND GOATS [ Vol. XXVI, Part III
Work so far carried out here indicates that deficiency of vitamin B 1 in sheep
and goats plays some part in the etiology of lumbar paralysis. It has not been
possible to establish so far as to whether the deficiency is primary, i.e. as a result of
deficiency of the vitamin in the fodder or is secondary, i.e. due to some factors
causing interference in the vitamin B complex in the rumen of the animals. The
possibility of trace elements, copper, cobalt and iron has been explored and it
appears that copper and cobalt may be the factors responsible for interfering with
the vitamin B synthesis in rumen of the affected animals.
SUMMARY
1. An obscure disease occurring amongst sheep and goats at the Government
Livestock Farm, Hissar has been described.
2. The results obtained with administration of thiamine in the treatment of
clinical cases of the disease have been reported to be encouraging.
3. The effect of administration of trace elements, copper, cobalt and iron, on
the incidence of the disease has been studied and it appears that a deficiency of
trace elements plays some part in the causation of the disease.
4. It has neither been possible to isolate any pathogenic organism from the
affected cases, nor the disease could be reproduced in sheep, goats and laboratory
animals.
ACKNOWLEDGMENT
The authors feel indebted to Shri B.N. Handa, Director Animal Husbandry
and Warden of Fisheries, Punjab, Simla for useful suggestions, to Dr Tulsa Ram,
Veterinary Investigation Officer, Punjab, Hissar for continuous interest and advice
during the course of investigation and to Shri M.R. Dhanda, Head of the Pathology
and Bacteriology Division, Dr N.D. Kehar, Head of the Division of Animal Nutrition
and Shri P.R.K. Iyer, Research Officer, Disease Investigation, Indian Veterinary
Research Institute, for guidance and examination of the materials sent to them.
REFERENCES
Crawford, M. (1939-42). Ann Repts. Govt. Vet. Surgeon, Ceylon
Ensminger, M.E. and Bowland, J.I. (1947). J. Anim. Sci. 4, 409-423
Hutyra, F., Marek, J. and Manninger, R. (1949). Special Pathology and Therapeutics of Diseases of
Domestic Animals, 5th. Ed. Vol. III
Innes, J.R.M., (1951). Brit. Vet. J. 107,187
Iyer, D.N. and Seetharaman, J. (1953), Indian Vet. J. 30-142,137
Innes, J.R.M., Shoho, C., and Pillai, C.P., (1952). Brit. vet. J. 71,83
Johnson, B.C., Hamilton, T.S., Nevens, W.B. and Boley L.E. (1948). J. Nutrition, Feb 10, 35-2
Olafson, P. (1946). Cornell Vet. 30, 141.
ACUTE THEILERIASIS IN SHEEP
By K. RAGHVACHARI and A. MADHAVAKRISHNA REDDY, Veterinary Investigation
Officer's Laboratory, Hyderabad-Deccan
(Received for publication on February 12, 1955)
A perusal of the available literature on the subject of theileriasis in sheep
indicates that only two species of Theileria parasites have so far been
recorded in sheep and goats and designated as Theileria ovis and Theileria herci.
The former parasite is considered non-pathogenic because it does not produce any
clinical symptoms of disease while the latter is associated with a definite and recog-
nisable fatal disease. In Theileria herci infection, besides the small ring or rod
shaped parasites in the red blood cells of sheep and goats, structures which are
interpreted as Koch's blue bodies have been encountered in blood and organs
including bone-marrow.
During the monsoon frequent deaths at the Mahbubnagar Farm
occurred in sheep and the Manager who was unable to diagnose the cause of death
sought the help of the senior author who visited the place of outbreak and examined
the (11) ailing cases. On examination of blood smears it was found that the cause
of death was acute theileriasis. These theilerial parasites were found along with
Koch's blue bodies, both free and in the large mononuclear leucocytes, in the blood
smears.
A lamb of about one year age was sub-inoculated intravenously with 20 c.c.
of blood direct from an ailing case showing high temperature and theilerial parasites
with Koch's blue bodies in the circulatory system. This lamb reacted after 16
days and the strain has been maintained in the laboratory.
The article is a preliminary note and the detailed experiments covering
all the aspects with regard to modes of infection, treatment, method of immunisation,
preventive measures, etc. are on hand and are being worked in greater detail and the
data accruing on this will form the subject matter of a further detailed report.
With a view to find out the host specificity of the strain, 6 goats, 2 buff-calves
and one cow-calf were sub-inoculated intravenously with 20 c.c. of blood, but all
these animals proved refractory to infection, whereas all the sheep sub-inoculated
simultaneously along with these animals in batches on different dates with the same
strain had reacted and succumbed to the disease, proving thereby that the strain is
specific only to sheep. Two rabbits and two guineapigs which also received 5 and
3 c.c. of virulent blood respectively did not react.
123
12 AR/56
7
124
ACUTE
THEILERIASIS
IN
SHEEP
[ Vol. XXVI, Part III
According to literature the pathogenic strain of theileria, viz. Theileria herci,
is a parasite which affects both sheep and goats. But the strain, which we have on
hand, appears to distinguish itself from Theileria herci in being specific to sheep
only in our host specificity experiments conducted so far. At first we hazarded
to call it a new strain, of which there seems to be very little doubt, yet we refrain to
call it so until we complete our programmed work on all aspects.
Sulphamezathine 33 1/3 per cent when inoculated intravenously in doses of
5 to 7 c.c. supported daily by half the initial dose, gave roughly 70 per cent recoveries.
Few deaths which could not be avoided in the apparently recovering cases about
one week after their reaching normal temperature were due to extreme emaciation
and damage caused by the disease to the vital organs like liver, spleen, kidneys and
lymphatic and alimentary systems and aggravated by heavy worm burden. These
cases were microscopically negative for the presence of the parasites on death.
The disease could be controlled satisfactorily by resorting to dipping and Copper's
dip, a patent, was utilised in the field for this purpose. Two varieties of ticks have
been collected off the ailing sheep and these are (i) Hyalomma sowignyi
(Gervais, 1844) and (ii) Rhipicephalus haemaphysaloides (Supino), the former being
predominant. Experiments are designed to transmit the disease through the agency
of ticks and their progeny to see whether one or both the species of the above men-
tioned ticks are vectors in this disease.
REFERENCES
Gaiger, S.H. and Davies G.O. (1938). Vet. Pathology and Bacteriology, 390
Richardson, U.F. (1948). Vet. Protozoology, 59
Wenyon, C.M., (1926). Protozoology, 1037.