226 



ANIMAL PHYSIOLOGY, 



Schwalbe and Loven. These are structures -which are found 

 nowhere else but on the protected sides of the circumvallats 

 papillae. Each cone occupies the whole thickness of the 

 epithelium; its base is on the papilla, its apex at the sur- 

 face, and its sides are convex. It consists of vertically 

 placed nucleated cells running the whole length of the cone, 

 the outer of which are flattened like the staves of a barrel, 

 and form coats like those of an onion, while the inner are 

 rod-shaped, and some of them with hair-like extremities, like 

 the olfactory cells; and the group of these extremities at the 

 top of each cone projects into the fossa round the papilla, 

 through a small opening left between the flattened superficial 

 cells of the surrounding epithelium. 



Fig. 112. TASTE-CONES OF SHEEP. A, Vertical section of circum- 

 vallate papilla, exhibiting seven taste-cones on each side. B, 

 Outer cells of taste-cone. C, Inner cells. Schwalbe. 



167. All tastes are not perceived by the same means. Astrin- 

 gents are perceived when applied to the fore part of the 

 tongue, but not when applied to the back part. Bitters are 

 perceived when applied to the back part, but do not affect 

 the fore part. Sweet and saline tastes are perceived by 

 means of both the fore and back part, but most acutely by 

 the fore part. If sugar be laid on the tip of the tongue, the 

 sweetness is at once perceived, though not so acutely as after 

 pressing the tongue to the palate; but it may be rubbed into 

 the back of the tongue, as also into the palate, without any 



