360 QUEENSLAND AGRICULTURAL JOURNAL. [L Oct., 1899. 
thoroughly ascertained,” or, in other words, that the serrated edge, and the 
indentations in the margins of the scales which form that edge, are the 0 y 
cause to which the felting property of the wool is to be ascribed. Youatt Va 
cautioned at the time by an optician of note against allowing himself to 
carried away by his enthusiasm in exaggerating the form of the epiderm aon 
overrating the importance of it. That gentleman wrote to him: “There 1 
appearance whatever of indentations upon the edges, and the only different? 
found was that the markings we observed upon the surface were more distin¢ y 
made out, and had more the wavy appearance than before. I am satisfied t : 
hair is round and cylindrical.” “Most thorough investigations by means of the 
microscope, made by the ablest men of the age, all coincide in the opimion ae 
the wool fibre has no hooks, branches, or a feathered edge, and that the mang 
of the epidermal scales do not protrude to such a degree as to give the whole 
strongly serrated look. 
The cortical substance is situated immediately under the cuticle, and it 
makes up the body of the hair shaft. It is composed of small spindle-shap 
cells which have completely turned into horn substance. They are. 10 et 
elliptic, or flat, and they are placed in concentric layers round the longitudin’, 
axis of the hair. In young hairs they run out in a pointed end, and the haw, vs 
which the point has been cut off, will always remain blunt. After disease 
however, and other circumstances which made the hair come off, the new shat’ 
reappears with a pointed top. In Todd and Bowman's “Physiological Anatomy 
we find the following description :— ; . 
_ The shaft is produced by the rather abrupt condensation and elongatio? 
into hard fibres of the cells. These fibres may be demonstrated by simpy 
crushing small fragments of the hair, but they become more conspicuous Whe 
the tissue is softened by a strong acid. 
The several kinds of hair and wool greatly differ in colour, which is pre Hi 
pally the result of the quantity of pigment distributed throughout the corts 
substance. It has the form of either granules, of which several are united 1° 
small heaps, or of a colouring fluid which pervades the cortical substance 11° 
one end to the other. 
. ; res 
_ The granules of pigment assume a linear arrangement between the fibré 
which are firmly united into a solid rod by a material similar, it may be suppo*® 
to that which cements the scales of the cuticle. 
' f F » Jess 
The absence of pigment cells imparts to the hair or wool a more or !@ 
white appearance, 
The white colour of the hair varies from a glassy, semi-transparent hue a 
that of the whitest china. Some wools have a silvery shimmer. ‘This, howev? 
cannot be accounted for simply through the absence of any kind of pigmeh™ 
but through the peculiarity of the cortical cells themselves. ‘ 
Lhe Medullary Substance-—This substance is situated in the centre of ee 
hair, and consists of cells which have kept more or less the characteristics 4 
the original cell. The medullary cells are either filled with air or conglomerat i 
into more solid layers, which are surrounded by air; some of them have ns 
and granules of pigment. The medullary substance is of a more or less por? a 
nature, while the cortical substance is far more solid and firm. All cone 
kinds of hair have a medullary substance, which can easily be seen on the brist a 
of pigs, white hairs of the human head, &c. There is no medullary substance 
real wool hairs, such as the wool of sheep, the down of goats, &c., and t in 
essential difference between hair and wool may thus be defined as consisting vf 
the presence of a medullary substance in the former and the perfect: solidity 
the latter. It is evident that the peculiar construction of the wool fibre accov® 
sufficiently for many of its SATHAEIS qualities, and we apply, according to oy 
foregoing explanation, the name “wool” to that class of animal hairs which ye 
no medullary substance ; such may be fine or coarse, long or short, straight 
waved, as 
