8
At 10-45 A.M.. Tabanidæ were seen on the smeared camel, and for
the next hour Tabanidæ were as frequently seen on the five unsmeared camels
and ponies. No Tabanidæ attacked the dogs during the period of observation.
Result.—Three pints of castor oil smeared on a camel prevents Tabanida3
from biting for only one hour,
37. Experiment III.—Three camels were used in the experiment, one
camel being smeared with the oil and the remaining two acting as controls.
Four pints of castor oil were applied at 8-30 A.M..
1st day.—At 9-50 A.M.. Stomoxys and ordinary house flies appeared on the
two controls and were present nearly the whole clay till evening.
None how-
ever settled on the smeared camel, though three or four times they approached
the smeared camel but did not settle.
At 11 A M. Tabanidæ appeared on the controls, and with the exception of
the hours from 2-30 P.M. to 4-0 P.M. (when very few flies were about) Tabanidæ
attacked the 2 controls till 7 P.M. No Tabanidæ, however, attacked the smeared
camel though several times they approached but did not settle, save once when
a Tabanus settled for an instant but Hew away without sucking.
2nd day 6-15 A.M.. to 8-30 A.M.. Stomoxys and ordinary house flies on
both the controls but none on the sprayed camel These flies were present more
or less the whole day till evening, and although they approached the smear-
ed camel not one was observed to settle
From 11.40 to 7 P.M. Tabanidæ were numerous on the 2 controls but
none attacked the smeared camel, and did not even settle on him except on
3 occasions when Tabanidæ settled for an instant but immediately flew away
without sucking.
3rd day,—Stomoxys and ordinary. flies were present on both controls
from 8 A M. to 6-30 P.M. A few Stomoxys settled for a, few seconds on the
smeared camel but did not bite. Tabanidæ were numerous on both controls at
various times during the clay but none were observed on the smeared camel.
4th day.—Stomoxys and ordinary house flies settled on the controls and
also on the smeared camel and Tabanidæ were numerous on both controls.
A few Tabanidæ were observed to settle on the smeared camel.
5th day.—Stomoxys, Lyperosia and ordinary house flies were observed
on the two controls and on the smeared camel. Tabanidæ were numerous on
the 2 controls and were also observed on the smeared camel, but not nearly to
the same extent as on the unsmeared camels.
6th day. Stomoxys and ordinary house flies were observed on the two
controls and the smeared camel Tabanidæ were also observed but were more
numerous on the unsmeared than on the smeared camel.
Remarks.—It is possible that castor oil may have a harmful effect upon
the skin, as it is liable, when exposed to the air, to thicken and form a varnish
like film. No harmful effect has, however, yet been observed.
Result.—(1) Pour pints of castor oil when smeared on a camel pre-
vents Tabanidæ and Stomoxys from biting for three days.
(2) From, the 4th to 6th day Tabanidæ were far less numerous on the
smeared camel than on the unsmeared.
CASTOR OIL EMULSION.
38. Experiment IV—As the result obtained by smearing with 3 pints
of castor oil was very different from the result obtained by smearing with 4
pints it was decided to repeat the experiment with 4 pints.
One camel was smeared with 4 pints at 9-30 A.M.. of castor oil and one
unsmeared camel acted as control. The camels were kept close to water and
tied at a short distance from one another.