NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
338
Vitamin A Study of Ghee
TABLE II
Effect of treatment with hydrogen at 100°C and 10 atmospheres pressure
Source of ghee sample
Tiruppur .
. . .
Gujarat .
.
.
.
Tiruppur (free acids neu-
tralised).
Kathiawar . .
„ + added oleic acid
„
„
„
Imperial Dairy Institute .
+ added oleic acid .
„
„
Time of
reaction
hr.
0
1
2
3
0
1
3
4
6
0
1
2
4
1
1
1
1
1
1
1
1
1
Acid
value as
oleic acid
per cent
3.53
3.53
3.46
3.40
2.77
2.64
2.64
2.70
2.64
..
..
..
..
0.95
1.45
1.96
2.48
3.04
0.38
1.41
1.96
2.35
Peroxide
value
(ml.
0.002 N
thio.
sulphate)
11.2
8.9
7.4
6.1
9.9
8.4
7.3
7.0
5.8
10.8
9.1
8.0
6.7
3.1
2.9
2.9
2.0
2.1
2.5
2.2
1.8
2.7
Lovibond
Blue
value
Yellow
value
per gram of butterfat
4.4
7.7
7.7
5.5
19.8
11.0
13.2
15.4
16.5
4.4
5.5
4.4
2.2
14.3
11.0
121
14.3
8.8
33.0
29.7
31 .9
27.5
0.5
0.5
0.6
0.5
0.3
0.3
0.4
0.3
0.3
0.3
0.2
0.2
traces
0.7
0.5
0.8
0.4
0.6
1.4
1.6
1.4
1.0
S. V. GOVINDARAJAN AND B. N. BANERJEE 339
Table II shows that the peroxide value was reduced by the hydrogen treat-
ment. The reduction of the amount of active oxygen and hence the decrease
of pro-oxygenic factors in ghee can only be advantageous from the point of
improving and keeping up the quality of ghee. The acid value is not altered ;
heat and treatment with hydrogen do not break down the glycerides. In
ghee samples showing high acid values and low vitamin contents, the hydrogen
did not increase the vitamin values. In the presence of large amounts of
free acid, a great part of the vitamin A is oxidised probably to compounds
which cannot be reverted to vitamin A by the action of hydrogen. But with
ghee samples where the acid values had been artificially increased by the
addition of oleic acid, and with a short period of contact with the acid, there
was no difficulty in regenerating the vitamin which had previously been
rendered inactive. If the same samples of ghee were left in contact with free
acid for a prolonged period and subsequently treated with hydrogen under
pressure, the vitamin recovery in no case approached the amount lost during
storage in contact with acid. These experiments (Table III) confirm the
previous statement that the presence of free acid helps to oxidize the vitamin
into inactive compounds.
TABLE III
Vitamin content of ghee left in contact with free acid, examined at the end of
three weeks, before and after hydrogen treatment
Source of sample
Imperial Dairy Institute
(untreated).
„
+ added oleic acid
„
„
Kathiawar (untreated) .
„
+ added oleic acid
„
„
„
Acid value
per cent
0.38
1.41
1.96
2.35
0.95
1.45
1.96
2.48
3.04
Lovibond
Blue values per gram
Initial
27.5
..
..
..
4.4
..
..
..
..
3 weeks
26.4
20.9
17.6
15.4
3.3
4.4
2.2
trace
trace
After treat-
ment with
hydrogen
after 3 weeks
storage
34.1
22.0
23.1
19.8
9.9
5.5
trace
trace
trace
340
Vitamin A Study of Ghee
Treatment of ghee with hydrogen in the presence of platinum catalyst.—
From the observations made earlier it may be assumed that part of the vitamin
A of ghee is oxidized to a form which does not give a blue colour with anti-
mony trichloride solution. The treatment of ghee with hydrogen reduced
the oxidized forms to a compound which reacted with that reagent. If this
were the case, then treatment with hydrogen in the presence of a catalyst,
where the process of hydrogenation takes place, would result in similar but
more thorough changes. The treatment with hydrogen under pressure was
repeated on samples of ghee in the presence of platinized asbestos. It was
found that the blue value was increased as before, and that the yellow value
was also increased slightly. The blue colour however was not of the same
tint, but was slightly purplish.
TABLE IV
Effect of treatment with hydrogen in presence of catalyst
pressure—10 atmos.
Source of
sample
Gir . .
Kathiawar .
Gujarat . .
Tiruppur .
Temp.
°C
..
100
„
..
100
„
„
..
100
„
„
..
100
„
„
Time of
reaction
hr.
0
1
2
0
1.5
2.5
4
0
1
3
6
0
1
2
4
Acid
value
per cent
oleic acid
0.38
0.38
0.32
0.95
0.95
0.82
..
2.72
2.66
..
..
3.47
3.40
3.34
3.40
Peroxide
value
(ml. 0.002
N thio-
sulphate)
5.4
3.2
2.1
4.3
2.8
2.2
1.7
9.9
7.6
5.7
1.5
11.2
6.4
4.8
1.8
Lovibond
Blue
value
per gram of
35.2
38.5
36.3
4.4
13.2
6.6
4.4
19.8
19.8
16.5
12.1
4.4
6.6
5.5
3.3
Yellow
value
butterfat
1.0
1.2
1.1
0.8
1.0
1.2
1.0
0.3
0.5
0.4
0.2
0.5
0.7
0.5
0.4
As in previous work the hydrogen treatment did not affect the acid value
of the ghee, but there was a rapid and greater decrease in the peroxide values
indicating a more rapid decomposition of these compounds. The reaction in
the presence of a platinum catalyst was similar to that when no catalyst was
used.
S. V. GOVINDARAJAN AND B. N. BANERJEE
341
Effect of adding carotene to ghee before treating with hydrogen.—Since the
hydrogen treatment in the presence of a hydrogenating catalyst increased
both the blue and the yellow values it indicated that part of the chromogenic
substances affected by the hydrogen treatment was carotene or related com
pounds. Carotene itself gives a blue colour with antimony trichloride due to
the β ionone grouping in the molecule. It was considered valuable to investi
gate the effect of adding carotene to a ghee poor in both vitamin A and caro
tene and to follow the changes taking place on treatment with hydrogen.
Carotene (90 per cent of β carotene) isolated from mangoes was added to
different ghee samples and subjected to hydrogen under pressure, both in the
presence and absence of catalyst. The results are shown in Table V.
TABLE V
Effect of adding carotene to ghee and treating with hydrogen at 10 atmos. pressure
and 100°C
Source of sample
Tiruppur (acid type)
.
.
.
.
„ + carotene
.
.
.
.
.
„
„
„
„ + carotene+ platinum catalyst .
„
Tiruppur
(neutralised
and
washed)
+ carotene
„
„
Kathiawar
.
.
.
.
.
.
„ + carotene
.
.
.
.
.
„
„
Time of
reaction
hr.
0
0
1
2
4
1
2
0
1
2
0
0
1
2
Lovibond
Blue value
Yellow value
per gram of butterfat
4.4
23.1
19.8
15.4
4.4
12.1
6.6
26.4
24.2
17.6
4.4
22.0
18.7
14.3
0.5
0.1
4.5
2.2
1.0
1.7
0.4
5.9
5.6
4.9
0.8
5.3
4.8
4.7
In no case was the added carotene able to withstand the treatment with
hydrogen at this temperature. The destruction of carotene was rapid in the
presence of the catalyst and free acidity also caused rapid destruction. The
addition of carotene to ghee of low vitamin contents before treatment with
hydrogen serves no useful purpose.
342
Vitamin A Study of Ghee
Effect of reducing the acidity of high-acid ghee before hydrogen treatment.—
It has been mentioned earlier that treatment with hydrogen of ghee of high
acidity does not increase the vitamin values, since a considerable amount of
the original vitamin has been changed into inactive forms. In order to over-
come the inhibitive effect of acidity, the ghee samples were neutralised with
alkali, washed free from soap and dried. The purified ghee was then treated
with hydrogen both in the presence and absence of catalyst. Table VI shows
that no improvement in the amount of vitamin recovery resulted from this
treatment. This showed that the changes in the vitamin had proceeded to
such an extent that it was impossible to regenerate the vitamin by a simple
hydrogenation process.
TABLE VI
Effect of neutralising free acidity before submitting to action of hydrogen at 100°C
and 10 atmos. pressure
Source of sample
Tiruppur
.
.
.
.
.
.
Tiruppur + platinum catalyst . .
Time of
reaction
hr.
0
1
2
4
1
4
Lovibond
Blue value
Yellow value
per gram of butterfat
4.4
5.5
2.2
2.2
5.5
5.5
0.3
0.2
0.2
traces
0.6
0.5
The question whether it is possible to regenerate all the vitamin in ghee
lost in storage or by causes other than those due to the presence of free acids
naturally suggests itself. It has been found that the regeneration of vitamin
A can be achieved only when the oxidation changes have not gone too far and
that there still remain some antioxidative compounds in the fat. These pro-
tective substances prevent the oxidation of vitamin A to compound from
which the vitamin cannot be regenerated by treatment with hydrogen. When
the degree of oxidation is such as to cause the inactivation of these antioxi-
dants or when the vitamin is degraded to some form that does not give a
blue colour with antimony trichloride, it fails to react with this reagent after
treatment with hydrogen.
A sample of ghee, rich in vitamin A, was heated in an atmosphere of oxygen
at 95°C to bring about destruction of the vitamin. The destruction of the
vitamin was followed by drawing samples at different intervals of time, and
this was taken to simulate the destruction brought about by long periods of
storage. The samples of ghee taken out were treated with hydrogen under
pressure to ascertain the extent to which vitamin A could be recovered.
Table VII gives the results of these experiments.
Ind. Jour. Vety. Sci. & Anim. Husb., Vol. X, Part IV ]
[
PLATE
XXIII
FIG. 1
FIG. 2
S. V. GOVINDARAJAN AND B. N. BANERJEE
343
TABLE VII
Regeneration of vitamin A in ghee heated for different periods
Samples of ghee (Jersey) heated in
oxygen
Time in hr.
0
2
5
10
20
Vitamin values
Blue
48.4
41.8
33.0
26.0
0.0
(Red units
2.2)
Yellow
24.0
22.0
18.0
12.0
0.1
Peroxide
value
4.6
5.5
6.2
7.2
28.4
Vitamin recovery on subsequent
hydrogen treatment under pressure
of same sample
Blue
value
..
46.2
41.8
40.7
0.0
(Red units
1.1)
Yellow
value
..
20.0
18.0
14.0
0.1
Peroxide
value
..
3.1
4.2
5.4
13.1
In a period of 12 hours of heating the destruction of vitamin A is not
extensive, but all the vitamin is destroyed in 20 hours. In every sample
where some vitamin remained, it was possible to recover the vitamin by
hydrogen treatment but where all was destroyed, it was not possible to
regenerate any of the vitamin. The antioxidants of butterfat prevent
autocatalytic oxidation of fat only as long as they are not inactivated ; as
soon as they are destroyed, vitamin A is rapidly attacked. The presence of
active antioxidants in ghee is a guarantee that all the vitamin is not inactiva-
ted or oxidised to such an extent that it cannot be regenerated by treating
with hydrogen.
Resistance of vitamin A in ghee to destruction by heat after hydrogen treat-
ment.—The beneficial effect of treating ghee with hydrogen so as to reduce the
peroxide content is also shown in the resistance of the vitamin to destruction
by heat. The ghee after treatment with hydrogen at 100°C and ten atmos-
pheres pressure (without any catalyst) was able to withstand a longer period
of heating before all the vitamin was destroyed than a similar sample of ghee
which has not been so treated (Plate XXIII, fig. 1). Since the initial peroxide
value in the hydrogen treated sample was lower than in the untreated
sample, it required a longer heating period to raise the peroxide content
to a high value than that required for the untreated sample.
Nature of the chromogenic substances.—It has been assumed up to the
present that the substance forming the blue colour with antimony trichloride
is vitamin A or closely related compounds and that the increase in the blue
value obtained after treatment with hydrogen is due to regeneration of vitamin
S. V. GOVINDARAJAN AND B. N. BANERJEE
345
By careful chromatographic separation vitamin A has been separated
into the predominant β fraction and the minor α constituent [Karrer et al.,
1933]. The β fraction gives the blue colour with antimony trichloride with
absorption maxima at about 620 m µ, while the α constituent gives one at
580 m µ. From observations made in the present work, it is probable that
both of these constituents are present in ghee, and that treatment with hydro
gen affects both of them. The reduction with hydrogen in the presence of
a platinum catalyst affects the α relatively more than the β fraction, while
the reverse is the case when there is no catalyst used.
Plate XXIII, figs. IIA and IIB show the absorption spectra of the blue
colours formed from the untreated ghee (Gir) and the same ghee treated with
hydrogen under pressure without catalyst. The two bands with maxima at
615 mµ and 575 m µ are clearly seen in each case. However, in the hydrogen-
treated sample, the 615 m µ band is more intense than the latter band. The
intensity of the absorption bands in the figures are not exactly comparable
because of the variation in the times of exposure of the two spectra.
It is therefore seen that this process of hydrogen treatment has great pos
sibilities for use in India where a large percentage of market samples of ghee
are generally very poor in vitamin A. By this means it should be possible to
rectify losses of the vitamin due to defective method of preparation, clarifica
tion and storage.
SUMMARY
1. The loss of vitamin A in ghee occurs as a result of the changes taking
place in storage or exposure to heat and air. Treatment of such ghee with
hydrogen under pressure is found to regenerate the vitamin. The optimum
conditions of temperature and pressure necessary for the recovery of the
vitamin A activity have been worked out. This treatment is attended with
an additional advantage in that the amount of active oxygen in the peroxide
form in the fats is reduced.
2. Evidence from the absorption spectra of the blue colour formed with
antimony trichloride shows that the increase in intensity of the blue colour
corresponds to an increase in the intensity of absorption at 615 m µ and there
fore represents an increase in the true vitamin A content.
REFERENCES
Banerjee, B. N. and Dastur, N. N. (1937). Agric. and Livestock in India 7, 24.
Banerjee, B. N. (1938). Agric. and Livestock in India 8, 153.
Coward, C. H., Dyer, F. J. and Morton, R. A. (1932). Biochem. J. 26, 1593.
Duliere, W., Morton, R. A., and Drummond, J. C. (1929). J. Soc. Chem. Ind. 48, 316T.
Karrer, P., Walker, O., Schöpp. K. and Morf, K. (1933). Nature 132, 26.
Lea, C. H. (1931). Proc. Roy. Soc. B 108, 175.
Lester Smith, E. and Robinson, F. A. (1937). Chem. and Ind. 56, 8, 190.
Mattill, H. A. (1931). J. Biol. Chem. 90, 141.
Morton, R. A. and Heilbron, I. M. (1928). Biochem. J. 22, 987.
Osborne, T. B. and Mendel, L. B. (1920). J. Biol. Chem. 41, 549.
Robinson, F. A. (1937). Chem. and Ind. 56, 8, 191.
THE LIFE-HISTORY OF BOOPHILUS AUSTRALIS
(FULLER)*
BY
S. N. SAPRE, B.Sc., G.B.V.C.
Research Scholar, Imperial Veterinary Research Institute, Mukteswar
(Received for publication on 9 May 1940)
M ATERIAL for the following observations, starting from September
1937, was collected from various sheds and outkraals at Mukteswar.
An adequate supply of replete females is available in this locality from the end
of September to the beginning of November. The observations were made
under laboratory conditions, and also in the field whenever possible. The
original intention of the author was to work out the life-histories of the com-
monest Indian ticks, under ordinary Indian field-conditions, but this intention
had to be modified and the work to be carried out at Mukteswar, the altitude
of which is 7,500 ft. above sea level. Consequently these observations may
not be wholly applicable to the conditions obtaining in the plains.
ECOLOGICAL CONSIDERATIONS
Boophilus australis would appear to be sufficiently adaptable to overcome
the adverse atmospheric conditions existing at Mukteswar. The eggs of these
ticks are known to be very resistant to changes in temperature and humidity,
being capable of withstanding the effects of as low a temperature as 15°F. It
is noteworthy that normally in this locality no other species of tick is found to
infest cattle. The parasite completes two generations in one year. The
first generation of the year is hatched in April and survives to the end of June.
This generation is numerically small as compared with the succeeding one,
for the following probable reasons. Firstly, the eggs of the first generation
have to withstand winter conditions, and, owing to the excessive cold, com-
paratively few of them remain viable ; secondly, the summer climate at Muktes-
war is not very suitable for these ticks on account of the comparative lack of
humidity. This generation, however, serves the purpose of maintaining the
local tick population during winter and early summer. The writer's experience
shows that the gravid females of this generation, at the end of June or there-
about, drop off the host and seek refuge in crevices where they oviposit. The
second batch of eggs hatch out by the middle or end of July. It has been
observed that, during August and early September, cattle, returning from
grazing, harbour actively feeding seed ticks. These larvae reach the adult
stage during October and November and the fertilised females then drop off
for oviposition. The period of oviposition extends up to a month-and-a-half.
The larvae from these eggs constituting the first generation of the year hatch
out during March and April, but they are numerically very few in comparison
with the enormous number of eggs produced.
* Paper presented at the twenty-seventh session of the Indian Science Congress,
Madras.
( 346 )
S. N.
SAPRE
347
EXPERIMENTAL OBSERVATIONS
As already stated, studies upon the life-history of B. australis under
laboratory conditions were undertaken in the latter part of September, when
a large number of replete females become available. Three batches of ticks,
numbering sixty in all, were maintained in an incubator at 22°C together with
a glass of water to provide the necessary humidity. Individual ticks were kept
separately in tubes with strips of filter paper to provide sufficient hiding place
and darkness. The eggs laid by individual ticks were counted with the help
of apparatus specially prepared for the purpose in the laboratory on the lines
given by Nuttall [1913]. Nuttall used glass strips cut with a diamond pencil.
In using such strips, even edges are essential and the writer has found that
ordinary microscopical slides are much simpler to use for improving the count-
ing apparatus. The counting was done along the two sides of the rectangle
and the product of the two figures thus obtained gave a fairly accurate indica-
tion of the total number of eggs. The calculation was always made to the
nearest round number.
OVIPOSITION
Batch No. 1 comprising sixteen ticks collected on the 24th of October 1937
Serial
No. of
tick
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Aver-
age
Period
between
dropping
and
oviposition
Days
4
3
5
6
5
4
5
4
3
6
3
4
4
3
4
6
4.2
Duration
of
oviposition
Days
24
23
23
22
21
17
14 15
7
14
14
18
17
19
16
17
17.4
Period
of
survival
after
oviposition
Days
6
8
7
6
6
8
5
4
2
5
3
3
2
5
3
3
4.75
Number
of
eggs
laid
2430
2690
2565
2430
2565
2025
1275
2160
200
2295
1080
2430
2025
4555
3200
3375
2338
Period
between
commencement
of
oviposition
and
hatching
Days
32
37
41
39
35
35
32
43
Not viable
39
41
37
35
33
36
39
37
NOTE.—The time required for metamorphosis from egg to larva is reckoned from
the date on which the female began ovipositing to the day on which the first larvae
emerged from the egg-shells.
348
Life-history of Boophilus australis
Batch No. 2 comprising twenty-five ticks collected on the 26th of October 1937
Serial
No. of
tick
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Average
Period
between
dropping
and
oviposition
Days
5
4
4
7
6
4
5
7
6
4
4
4
4
3
4
4
4
4
5
5
5
6
6
4
6
4.2
Duration
of
oviposition
Days
16
15
16
16
20
19
20
20
19
18
18
16
24
23
22
21
15
16
16
17
14
18
16
20
15
18
Period
of
survival
after
oviposition
Days
5
5
5
6
2
3
4
5
4
5
6
5
3
3
5
6
3
6
4
4 8
4
5
2
4
4.5
Number
of
eggs laid
3375
2565
2700
1620
2600
2700
2430
4050
4725
2970
2700
1620
2700
2000
1300
1100
2500
2565
1755
2970
1215
1485
1890
2600
1465
2300
Period
between
commencement
of
oviposition
and
hatching
Days
42
37
39
43
47
Hatched few
41
36
37
39
42
45
39
41
38
39
Not viable
42
37
32
35
40
39
43
43
39
39.7
S. N.
SAPRE
349
Batch No. 3 comprising nineteen ticks collected on the 27th of October 1937
Serial
No. of
tick
1
2
3
4
6
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Average
Period
between
dropping
and
oviposition
Days
3
5
3
4
5
7
5
5
4
3
3
2
6
5
4
3
7
5
4.43
Duration
of
oviposition
Days
16
16
18
20
19
17
18
16
Period
of
survival
after
oviposition
Days
4
2
5
2
4
3
4
5
Number
of
eggs laid
2575
2250
2430
3775
2565
2160
2690
2025
Died without laying eggs
24
22
17
19
20
23
21
14
15
17
18
5
4
3
5
2
4
3
6
5
4
4.4
4725
4050
2970
2430
2700
4050
2970
1200
1620
2565
2451.7
Period
between
commencement
of
oviposition
and
hatching
Days
41
37
39
32
41
42
39
35
37
37
39
41
39
36
34
Not viable
43
39
38.57
B
S. N.
SAPRE
351
stalls as are readily accessible to them and oviposition soon follows. It has
been observed that gravid females usually drop off at a time when the host is
sitting down or standing quiet, as this largely precludes the possibility of their
being crushed under the feet of the host. It was observed that, on particular
occasion, such as when a green feed was being given to the host, a large number
than usual of the gravid females dropped off.
Observations on the duration of the parasitic stages of B. australis, in-
cluding the period required for the metamorphosis to take place, are summaris-
ed in the following tables. For these observations two batches of approxi-
mately 110 and 60 larvae were used. The larvae of the first batch were
fed by means of ear bags, while those of the second batch were applied to
the skin under the tail where they attached themselves immediately, without
wandering about in search of a more suitable place for attachment.
Batch No. 1
Host
Bullock
Bullock
Bullock
Date of attachment
to host
Date of
engorgement
Larvæ
10th
August
1938
9 A.M.-10-30 A.M.
13-8-38
Nymphs
17th— 19th
August
1938 (i.e. immediate-
ly after moult)
21-8-38—21
22-8-38—62
23-8-38—26
Adults
24th—26th
August
1938 (i.e. immediate-
ly after moult)
Date of issue of next
stage
17-8-1938—19
18-8-1938 (A.M.)—26
18-8-1938 (P.M.)—29
19-8-1938 (A.M.)—27
19-8-1938 (P.M.)—8
Total 109 nymphs
24-8-38 (A.M.)—12
24-8-38 (P.M.)—13
25-8-38 (A.M.)—39
25-8-38 (P.M.)—23
26-8-38 (A.M)—17
26-8-38 (P.M.)—4
Total 98 adults
(11 lost)
(No. of engorged females
recovered)
3-9-38 (P.M.)— 7
4-9-38 (A.M)— 4
4-9-38 (P.M.)— 16
5-9-38 (A.M)— 8
5-9-38 (P.M.)— 12
6-9-38 (P.M.)— 6
Total
53
B 2
352
Life-history of Boophilus australis
Batch No. 2
Host
Bullock
Bullock
Bullock
Date of attachment
to the host
Date of
engorgement
Larvæ.
17th August 1938 noon 20th—21st
August 1938
(P.M.)
Nymphs
23rd—25th
August
1938 (i.e. immediate-
ly after moult).
Adult
30th August 1938—4th
September 1938 (i.e.
immediately
after
moult)
27-8-38— 7
28-8-38—32
29-8-38—11
30-8-38— 6
Date on which next
stage issued
23-8-38 (P.M.)— 7
24-8-38 (A.M.)—14
24-8-38 (P.M.)—17
25-8-38 (A.M.)—11
25-8-38 (P.M.)— 7
Total 56 nymphs
30-8-38 (P.M.)—11
31-8-38
(P.M.)—20
2-9-38 (A.M.)—12
2-9-38 (P.M.)— 7
3-9-38 (A.M.)— 4
4-9-38 (A.M.)— 2
Total 66 adults
(No. of engorged females recovered)
11-9-38 (A.M.)—
11-9-38 (P.M.)—
12-9-38 (A.M.)—
12-9-38 (P.M.)—
13-9-38 (P.M.)—
14-9-38 (A.M.)—
Total
2
10
4
9
6
2
33
SUMMARY
The larvae of Boophilus australis, when liberated on the body of the ox,
seek a suitable place for attaching themselves. They take three days to feed
and four days more for metamorphosis, so that the larval stage lasts for seven
days from the day of attachment to the host. The nymphs take four days to
feed and four to five days for metamorphosis and the nymphal stage there-
fore occupies a period of seven to nine days. The adult feeds for ten to
eleven days and then drops off for oviposition. The pre-oviposition period
S. N.
SAPRE
353
ranges from two to seven days (average 4.4 days). The oviposition period
ranges from 14 to 24 days (average 18 days). The female tick survives after
oviposition for two to eight days (average 4.4 days). The number of eggs
laid by an individual tick varies from 200 to 4725 (average 2551.7). The
egg stage at 22°C lasts for 32 to 45 days, as reckoned from the commencement
of the oviposition to the emergence of the first larva (average 38.57 days).
ACKNOWLEDGEMENT
I am grateful to Rai Bahadur S. K. Sen, F.R.E.S., for his kind assistance
in this work.
REFERENCES
Nuttall, G. H. F. (1913). Parasitology 6, 73-74.
Sharif, M. (1924). Imp. Inst. Agric. Res. Pusa. Bul. No. 152.