September, 1954]
B.
B.
BUCH
AND
G.
S.
MAHAL
165
'Joria' wool comes from the carpet type wool which is defined as a mixture of
hair, wool and kemp fibres [Anonymous, 1947] and is also designated as mixed wool.
The common types of fibres constituting carpet wools are wool, heterotype, hair,
coloured fibres and kemp. Since carpet wools are a mixture of different types of
fibres which possess variable physical properties, a change in their proportion is
likely to alter the character and nature of wool for the manufacture of different
types of material. Various workers like Blyth [1923], Roberts [1926], Wilson
[1929], Lochner [1931], Elphick [1932], Darling [1932], Bulgaru [1935], Manz
[1937], Burns, Johnston and Chen [1940], and Mahal [1949], conducted analysis of
mixed wools and their basic procedure was to work out the proportion of different
types of fibres although using slightly different names in some instances. The
method is now universally adopted for the analysis of mixed wools. Although
the analysis of fibre types is a useful guide in evaluating the quality of mixed wools
from manufacturing view point, it does not give the actual amount of medullation
in a sample due to the varying amounts of medullated and non-medullated portions
in the heterotypes. The correct estimation, however, is essential for a critical
selection of sheep in any improved breeding programme. Accordingly, the medu-
llation test was carried out under two different techniques ; Fibre Count Analysis
and Projection Method for Medullation Test.
For the analysis by count, duplicate composite samples were separated into
different types of fibres by employing Elphick's [1932] benzol test. In case of
doubt a microscope was employed for the confirmation of results. The different
fibre types in each composite samples were counted and the percentage worked
out.
In the projection method for medullation test duplicate composite samples
were used for each type of wool. Hardy's [1935] thin section device was used for
making the sections. These sections were projected, using X 500 magnification,
on a white surface of 20 cm. diameter area, and the number of medullated and non-
medullated fibres in the different samples were determined. From these figures
the percentage of the two fibre types were calculated.
Measurements for stretched fibre length were made both of the composite
samples as well as the fibre types which were separated out in the count analysis.
Burns [1940] improved technique was used for these measurements. One hundred
and fifty fibres of each type were measured except when their total number in the
sample was smaller.
For fibre thickness measurements, the longitudinal short section method [A. S.
T. M., 1947] was employed. Thickness measurements of the composite samples
as well as of fibre types were made separately. Duplicate composite samples were
used in the former case and the fibre types separated in count analysis were used
in the latter case. The formula used by Roberts [1920] was employed in deciding
the minimum number of fibres to be measured for this purpose. Only 100 readings
were recorded to measure the fibre types.
RESULTS AND DISCUSSION
The results of medullation test both by fibre type analysis and projection
method are presented in Table I. The analysis by fibre count reveals that the