94
Villavecchia Reaction for Sesame Oil
for some time after it has warmed up. On the
Punjab farms, it is also to be noted that (1) a
secondary rise in the attack rate may occur in
May-June when for days on end there is a very
hot dry wind with liability to dust storms, and (2)
following several seasons of low incidence and re-
sulting increase in the local susceptibility, out-
breaks sometimes commence during the hot season.
In the endeavour to control strangles in the
Punjab, insufficient attention has been paid to the
necessity of protecting young horses from the
effects of extreme cold and winter rain.
ACKNOWLEDGEMENTS
I am grateful to Dr C. W. B. Normand and
Dewan Bahadur K. R. Ramanathan of the India
Meteorological Department, for providing the ne-
cessary data, and to Mr Suprakas Sen, Statistician
of this Institute for much assistance. I am also
highly indebted to Sir Edward Cole and Major
T. G. M. Harris of Coleyana, to Colonel R. Bruce
of Renala, and to Major M. F. Keightley, Army
Remount Depot at Mona for all possible help in
my enquiries.
REFERENCES
Allen, H. (1923);
Andrews, F. J. (1935);
Barry, W. E. (1938)
(Unpublished) Records of the
Mukteswar Institute
Boyd, E. M., and Johnson, G. M. (1940). Amer. J. Med.
Sci. 199, 246
Brown, W. A., and Allison, V. D. (1937). J. Hyg., 37, 1
Cralley, L. J. (1942). Amer. J. Hyg. 36, 303
Greenwood, M. and Thompson, T. (1907). J. Hyg., 7, 170
Loosli, C. G., Lemon, H. M., Robertson, O. H., and Appel,
E. (1943). Proc. Soc. Biol. & Med. 53, 205
Minett, F. C. (1944). Indian J. Vet. Sci. & Anim. Husb.
14, 1
Rogers, L. (1925). Lancet, i, 1173
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(1925-1). Brit. Med. J., i, 256
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(1926). Med. Res. Council, Special Rep. Ser.,
No. 106, H. M. S. O., London
Russell, A. J. H., and Sundararajan, E. R. (1928-9).
Indian J. Med. Res. 16, 559
Webster, L. T. (1927). J. Exp. Med., 45, 529
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and Burn, C. (1927). J. Exp. Med. 45, 911
White, E. (1936). Lancet, i, 941
Wilson, G. S. (1930). J. Hyg. 30, 196
Winslow, C.E.A., Herrington, L.P., and Nelbach, J. H.
(1942). Amer. J. Hyg., 35, 27
A STUDY OF THE VILLAVECCHIA REACTION FOR SESAME OIL
By NOSHIR N. DASTUR, K. G. BHIDE and ZAL R. KOTHAVALLA, Imperial Dairy Research Institute,
Bangalore
(Received for publication on 30 June 1943)
THE systematic studies by Villavecchia and
Fabris on the utility of the Boudauin test for
detecting the presence of sesame oil were
carried out in 1893. As no data are available
on the relation of the colour developed during
the reaction to the quantity of the oil present,
a detailed study was carried out to study the
effects of various factors on the colour develop-
ment in the Villavecchia reaction and further
to determine the possibilities of increasing the
sensitivity of the test in general use at present.
EXPERIMENTAL
The Villavecchia reaction is usually carried
out as follows [A.O.A.C., 1940].
A mixture of 0.1 ml. of 2 per cent alcoholic
solution of furfurol and 10 ml. of HCl are
shaken with 10 ml. of oil sample for 15 seconds
and the aqueous layer allowed to separate.
Instead of furfurol solution 0.1 gm. of finely
produced sugar dissolved in 10 ml. of HC1 can
also be used.
Taking this method of carrying out the test
as standard, the effect of different factors was
investigated, introducing appropriate modifica-
tions wherever necessary.
For the following studies (when not other-
wise mentioned) a 5 per cent solution of sesame
oil in groundnut oil was used. Both the sesame
and groundnut oils were pressed from pure seeds
and guaranteed to be genuine. The free acidity
was neutralized, and the oils dehydrated and
filtered before use. The red colour of the re-
action mixture was compared in the Lovibond
Tintometer using 1 cm. cell.
(i) Effect of using different strengths of hydrochloric
acid
Fuming HCl (sp. gr. 1.19) was diluted to
different strengths as indicated in Table I. To
match the colour quantitatively, the aqueous
coloured layer was pipetted in a centrifuge tube
and centrifuged at 2,500 r.p.m. for 5 minutes.
This helped to give a clear solution. The colour
was matched soon after carrying out the test.
The same solutions were then kept in a refri-
gerator overnight, and colours were compared to
see if there was any change in the colour on
longer keeping. The results are given in Table I.