144 



THE SHEPHERD'S MANUAL. 



parous glands), which are situated in the derma, amount to a total 

 quantity which surpasses that of the evacuations from both the 

 bowels and kidneys. 



In fig. 47 is shown the structure both of the skin and the hah*, 

 the engraving, (from Chauveau's Comparative Anatomy of the Do- 

 mestic Animals), representing a section of the skin highly magni- 

 fied. The epidermis is shown at A, the derma at B, the hair follicle 

 at c, the sebaceous glands at 1, the bulb or root of the hair at 2, the 

 hair at 3, a fat cell at 4, a sudoriparous or sweat gland at 5, and at 6 

 the excretory duct of this gland, or pore of the skin. 



Hair or wool is composed of three layers. The outer one, the 

 epidermis, is very thin, consisting of the flattened cells or scales 

 overlapping as previously mentioned. In wool these imbricated 

 cales are highly developed, and fill a most important office, giving 



Fig. 48. APPEABANCE OP WOOL WHEN HIGHLY MAGNIFIED. 



to it much of its value as a material for the manufacture of cloth. 

 When examined by a microscope of high power, a fiber of wool 

 presents the appearance shown in fig. 48. The discovery of the 

 serrated surface of wool which is generally attiibuted to Mr. 

 Youatt, was previously announced by M. Monge, in Annaks de 

 Chimie, in 1795. This serrated or toothed surface confers upon wool 

 its felting property. When wool is carded it is torn to pieces and 

 mixed and twisted in every direction. The waved or curved 

 structure of the fiber of some qualities of wool aids in this twisting 

 and entangling of the fibers, (see tig. 49), and the points of the 

 scales projecting as. so many minute hooks hold the entangled 

 maas togather closely and firmly. Pressing, rolling, or beating 



