84 ANIMAL PHYSIOLOGY. [LESSON 27. 



great attention within the last few years. The Genera of an animal, 

 and frequently the species, can be accurately determined by the mi- 

 croscopical examination of a fragment of a hair. 



In the higher mammalia, the hair appears to possess the same 

 tissues as those described as belonging to the human hair, that is to 

 say, the cuticle, the cortex, and the medulla. 



443. Allusion has been made to the want of vascularity of the 

 bulb of the human hair, and the interior of the follicle ; if the whis- 

 ker (vibrissa) of a cat be pulled out, it will generally bleed, proving 

 vascularity in the follicle, if not in the bulb, of these particular 

 hairs. 



444. If a thin, transverse section be made of a Tiger's whisker 

 (Fig. 131), the three tissues composing it are distinctly seen ; the 

 outer cuticular layer (a), the cortical substance (b), remarkable for 

 the great amount of pigmentary cells included in it; and lastly, the 



FIG. 18L FIG. 132. 



Transverse section, Tiger's "Whisker. Transverse section, Cat's Whisker. 



medullary cylinder (c) in the centre, containing well-formed pigment 

 cells, but devoid of pigment where this section was made. 



A similar section of a Cat's whisker (Fig. 132) shows the same 

 structure. 



445. The Vibrissse, as the whiskers of animals are called, are in- 

 struments of great importance to a vast number of them, but espe- 

 cially to the Feline races. All the cats, from the majestic lion down 

 to our household pet, are not only carnivorous (feed on flesh), but 

 they are predaceous (prcsda, prey), seize living prey. 



446. As soon as the eye discerns a victim, it is fixed with a deadly 

 and unfaltering gaze ; the creature creeps stealthily and noiselessly 

 along upon the soft cushions of the feet, the eye having no part what- 

 ever in the direction taken ; what then guides it ? the Vibrissae. 



The Vibrissse, measured from point to point, exceed the diameter 

 of the widest part of the body ; wherever they can pass without 

 touching, the body therefore can follow. Their sensibility appears 



