December, 1952] G. S. MAHAL, A. JOHNSTON AND R. H. BURNS 295
Before analysis the representative samples were scoured in order to remove
extraneous matter. The method of scouring suggested by Johnston [22] was
employed. Before analysis a final rinse in carbon tetrachloride was given. All
burrs or other vegetable matter were carefully picked out from each sample by
hand; the sample was then blended, by repeated splitting of the staples, for the
study of different characteristics.
Techniques used for Analysis
The various tests and determinations made in the analysis of the samples
included: medullation test; stretched fiber length measurements: fiber thick-
ness; contour ratio; and surface scale structure for fiber types.
Bikaner wool is of mixed type and contains different types of fibers—namely,
wool, heterotype, hair, colored fibers, and kemp. Except for the colored fibers,
the distinction between the fiber types is made according to the degree of medulla-
tion—no medullation (wool), partial medullation (heterotype), or complete medulla-
tion (hair). The kemp fiber is a characteristic "dead." fiber, and is comparatively
thick, short, straight, and in most cases opaque white like burnt bone.
Various workers, such as Blyth [9], Roberts [29], Wilson [33], Lochner [24],
Elphick [18], Darling [17], Bulgaru [12], Munz [25], and Burns, Johnston, and Chen
[14], conducted analyses of mixed wools; their basic procedure was to determine
the proportion of different types of fibers, although using slightly different names
in some instances. This is important because all the fibers possess variable physical
properties, and a change in their proportion is likley to alter the character and
nature of a wool. The method for the analysis of mixed wools has now been adopted
universally. Although the analysis of fiber types is a useful guide in evaluating
the quality of mixed wools from a manufacturing viewpoint, it does not give the
actual amount of medullation in a sample due to varying amounts of medullated
and non-medullated portions in the heterotypes. This estimation is essential
for a critical selection of sheep in any breeding-improvement program. Accord-
ingly, the medullation test was carried out under two different techniques—fiber-
count analysis, and cross-sectional medullation test.
For a counting analysis, duplicate composite samples were separated into the
different types of fibers by using Elphick's benzol test. However, it was found
necessary for efficient results that benzol, with a refractive index of 1.50, be employ-
ed. In case of doubt, a microscope was employed for the identification of the fibres.
A white paper background was used to identify colored fibers. Fibers in each class
were counted and their proportions worked out mathematically.
For the cross-sectional medullation test, duplicate composite samples were
used for each type of wool. Hardy's technique [19] was used in making cross
sections. Three sections were made of each sample—namely, one at the base, one
at the middle, and one at the tip. These sections were projected, using 500 X
magnification, on a white surface of 25 cm. X10 cm. area, and the number of medul-
lated and non-medullated fibers were counted and recorded. The total number of
medullated and non-medullated fibers in the different samples were determined.
From these figures the percentages of the two fiber types were calculated.
10A