1 Jan., 1900.] QUEENSLAND AGRICULTURAL JOURNAL. 5 
THE PRINCIPLES OF SHEEP-BREEDING. 
No. 6. 
By J. S. HERMANN SCHMIDT, 
THE STAPLE. 
On a former occasion I have mentioned how the wool fibres, whilst growing up 
from the skin, conglomerate into bunches of different size, called staples. ‘hey 
exhibit great difference in form, the result of the qualities and the structure of 
the single fibres of which the bunches or staples are composed. _We can thus 
form an approximately correct estimate of the qualities of the single fibres by 
taking notice of the shape and the whole external appearance- of the staples. 
Besides the qualities of the fibres themselves, there are two factors which 
exercise an influence on the manner in which the fibres arrange themselves into 
staples, viz.:—Ist, the yolk; 2nd, the density of their growth. _ 
Before treating on the shape of the staples, let me consider these two 
subjects first. ; j 
The Yolk.—The fatty substance found in any ordinary fleece is a mixture 
of a kind of soft soap and two different kinds of fat, elainerine and stearinerine. 
The skin contains, as I haye described before, two kinds of glands the sudori- 
parous or sweat glands, situated in the lower portion of the skin; and the 
sebaceous or fat glands, placed near the sheath of the shaft of the fibre. 
The sudoriparous glands are not so numerous and so well developed in the 
skin of sheep as they are in that of mankind. Sheep do not actually sweat, 
but, whilst there is no visible perspiration, the sweat glands nevertheless 
produce water, which, however, evaporates very rapidly. The sweat carries 
with it from the sweat glands ammonia and certain minerals, especially potash 
salts, which being in solution are absorbed by capillary attraction and brought near 
the wool fibres. The fat glands, of which there are mostly two to each fibre, 
produce a mixture of elainerine, an oily substance, and stearinerine, a more 
solid fat. These fats are partially turned into a kind of soft soap by the potash 
salts produced by the sweat. 
The quantity of potash brought up from the skin through the agency of | 
the sweat glands is so large that the recovery of it from the washings of sheep 
or wool has become an important industry in districts where large quantities of 
sheep or wool are washed. The potash combines with an animal fatty acid, and 
forms a substance called sudorate of potash. (Bowman.) 
_Yolk is therefore a mixture of a kind of soft soap, 
soluble in cold water, and thus easily washed out, and of 
more or less difficult to dissolve in soapy solutions. 
Coarse-woolled sheep produce less yolk than merinos. 
The quantity and the quality of the yolk depend upon—Firstly, the quantity 
of fat glands in the skin in proportion to the number of fibres on the square 
inch (density) ; hence the mure fibres the more yolk; secondly, on the quantity 
and the quality of the food consumed; and thirdly, on the individual nature 
of the animal. 
In Australia we have mostly grass-fed sheep. ‘Their yolk is more fluid, ’ 
and there is less of it than in the wool of stable-fed animals. 
The influence of the various kinds of grain, of root crops, of green fodder 
plants, &c., on the quantity and the quality of the yolk is so different that, 
i} Some cases, it is possible to say with a considerable amount of certainty that 
these or those sheep, as the case may be, have been fed with leguminous seeds 
(peas, beans, lupines, &c.), because they have a peculiar, sticky yolk, for which 
the scourer will not bless the producer . ee 
In countries where the sheep are fed with different kinds of food during 
certain periods of the year, those periods are recorded in the length of the staple’ 
by the difference in the consistency and the colour of the yolk. A diet of 
potatoes renders the yolk light-coloured and oily; that of beet root imparts to’ 
1t a look as if it had been sprinkled over with a yellow dust. 
sudorate of potash, 
other fatty matters 
