Testing Wool for Medullation
283
source. The digestible protein obtained from 80 lb.
of oats is equal to that obtained from 100 lb. and
starch equivalent from 86 lb. of mango-seed kernel.
The high digestibility coefficient of the protein
and nitrogen-free extract and the biological value of
the protein give the seed a place in the list of im-
portant food stuffs.
Work on the feeding of mango-seed kernel to
rats is in progress.
REFERENCE
Kehar, N.D. (1944). Indian J. vet. Sci. 14, 40
A NOTE ON A NEW METHOD OF TESTING WOOL FOR MEDULLATION
By P. N. NANDA, M.R.C.V.S., GURBAX SINGH, L.V.P. and S. B. MOGRE, M. Sc., Government Livestock
Farm, Hissar
(Received for publication on 21 October 1944)
(With Plate XIV)
OF the recognized methods of determining the
percentage medullation in wool, only McMahon's
Medullometer can be of use if a large number of
samples from individual animals are to be dealt
with. The other methods are too lengthy and
require several days to analyse a single fleece. The
use of the medullometer too is restricted to labora-
tories where electric current and technically trained
staff are available. With a view to guide field
workers, the authors have devised a simple rapid
test to estimate approximately the medullation
in wool. It is based on Elphick's benzol method.
It is known that a clean sample of wool when placed
under benzol exhibits an intensity of whiteness in
proportion to the amount of medullation in the
sample. Marked difference in whiteness can easily
be judged with the naked eye. For selecting sheep
carrying good quality wool, the easiest course is to
make small samples from these sheep, wash the
amples in petrol, take an equal quantity by weight
of all of them and place them side by side, under
benzol, in a black enamelled tray. From the in-
censity of whiteness in the samples, one can at once
pick out the samples from sheep carrying better
wool. This method can be used to pick out better
quality sheep, but for recording the percentage of
medullation in individual animals, which is so
essential for breeding on scientific lines, it does not
serve the purpose. To overcome this, certain
standards have been devised. These standards
show samples under benzol with different amounts
of medullation, varying from zero to 100 per cent.
For studying the approximate percentage of medul
lation in a sample, the same weight of the sample,
as in the standards, is placed under benzol and its
percentage determined by comparison. The method,
therefore, involves two main operations :
(a) Making of standard samples from different
breeds of sheep and
(b) Studying of samples in the field in comparison
with the standard samples.
Making of standard samples. Two hundred small
shoulder samples are taken from a particular breed
of sheep. After getting rid of the free vegetable
matter, each sample is first washed with a 1 per cent.
neutral soap solution at 50°C. and then rinsed twice
in petrol at the same temperature. After drying
them at the room temperature, 100 milligrams of
each sample are taken for making the standards.
All these samples are put under benzol in an enamelled
tray which can accommodate about 20 to 30 at a
time. Judging from the intensity of whiteness
shown, some samples showing varying amounts of
hairiness, can be picked out. These selected samples
are then arranged in series according to percentage
of the medullation in them. The first one represents
zero per cent and the last one 100 per cent. The
intervening samples are then allotted arbitrary per-
centage medullation in an ascending order to indicate
increased hairiness. The percentages fixed for the
samples are according to the intensity of whiteness
exhibited by them. To obtain sharp contrasts,
the first sample should consist of pure wool and the
last of pure hair. The estimation of medullation
would be more accurate if a large number of samples
are taken to make up the standards.
For more reliable results the percentage medullation
in the series may be fixed by actually ascertaining the
exact amount of medullation by the microprojec-
tion method. These standards can then be used for
the estimation of medullation in any given sample
of wool by comparison. To have standards handy
in the field, photographs of prepared sets can be
used with equal efficiency.
The technique consists in first taking a small
sample from the sheep as close to the skin as possible.
After cleaning it to get rid of all free vegetable
matter and dirt, it is given a free rinsing in petrol
for one to two minutes. It is then allowed to dry.
One hundred milligrams of the sample are then
weighed out by means of the portable balance.
This quantity is spread out a little between the