THE MICROSCOPE IN ZOOLOGY. 87 



arranged in the direction of the apex of the hair. The 

 colour of the hair is due to the presence of pigment- 

 granules and air-cells diffused through its substance. 

 The hairs of bats are very curious ; they have projec- 

 tions on their surface, formed by extensions of the 

 scales of the cuticle layer. The hair of a species of 

 Indian bat reminds one of the branch of an equisetum, 

 long, narrow, leaf-like scales being arranged round the 

 shaft in regular whorls. In the mole and other 

 insectivora the cells of the medulla are very distinct. 

 Amongst ruminant animals great variety occurs in the 

 structure of the hair, whilst the camel's hair exhibits 

 pretty nearly the same structure as that of the higher 

 classes. The musk-deer's hair consists almost entirely 

 of the inner medullary layer ; the cuticle layer is 

 nearly absent. Nor must we regard this structure of 

 the hair of animals merely as an interesting subject, 

 for as Mr. Gosse has well said, in his charming " Even- 

 ings at the Microscope," England's time-honoured 

 manufacture, that which affords the highest seat in 

 her most august assembly, depends on the imbricate 

 surface of hairs. "The hat on your head, the coat on 

 your back, the flannel waistcoat that shields your 

 chest, the double hose that comfort your ankles, the 

 carpet under your feet, and hundreds of other neces- 

 saries of life, are what they are because mammalian 

 hairs are covered with sheathing scales. 



" It is owing to this structure that those hairs which 

 possess it in an appreciable degree are endowed with 

 the property of felting; that is, of being, especially 

 under the combined action of heat, moisture, motion, 

 and pressure, so interlaced and entangled as to be- 

 come inseparable, and of gradually forming a dense 

 and cloth-like texture. The ' body/ or substance, of 

 the best sort of men's hats is made of lamb's wool 

 and rabbit's fur, not interwoven, but simply beaten, 



