CHARACTERISTICS OF WOOL AND HAIR. 



145 



the wool together, causes it to adhere in a compact mass, in 

 other words causes it to felt firmly together, and the more 

 firmly, the more it is rolled, beaten, or worked. These scales 

 are very minute and numerous; in the length of one inch of a 

 fiber of fine Saxony wool, there are no less than 2,720 of them ; in 

 Southdown wool there are over 2,000, and in the Leicester wool 

 there are over 1,800 of them to 

 every inch. Upon the whole sur- 

 face of a fiber of Merino wool one 

 inch long and V 75 o of an inch in 

 diameter, there are over 23,000 of 

 these points. The more numer- 

 ous they are, and the more waved 

 or curled the wool, the better its 

 f elting quality. 



The second layer, the cortical 

 substance, is the thickest portion of 

 the fiber. It also contains the 

 coloring matter. It is fibrous and 

 striped lengthways. The central 

 portion of the fiber consists of the 

 medullary substance, or marrow, 

 and occupies a narrow, irregular 

 cavity. Hair or wool is not hollow or tubular, as is frequently 

 supposed, but solid, and consists of these three portions. The fiber 

 grows from the root, and increases by addition of cells continuous- 

 ly formed in the follicle. It is thus seen that the growth and per- 

 fection of the wool depends in the most intimate manner upon 

 the nutrition and perfect health of the animal. An interesting 

 and valuable addition to the natural history of wool and hair has 

 recently been made through some investigation ordered by the 

 Secretary of the Treasury of the United States, for the purpose of 

 identifying the presence of sheeps' wool in manufactured goods, the 

 materials of which are ostensibly the hair of the cow and calf. 

 The investigations were made by Professors John L. LeConte and 

 J. J. Woodward, of Washington, D. C., with the help of a micro- 

 scope magnifying nearly 100,000 times, (310 diameters). The full 

 report of these investigators^ is published in the Bulletin of the 

 National Association of Worn Manufacturers, Yol. V, No. 7, 1875, 

 (Boston), a publication of the greatest value to intelligent wool- 

 growers as to all woolen manufacturers. After describing the well 

 known structure of hair and wool, the report proceeds : " But not- 

 withstanding this similarity of structure, most of the individual 

 7 



Fig. 49. FIBERS OP WOOL. 



