CONTRIBUTIONS TO ZOOLOGICAL AN ATOMY. 
277 
the bristles, and quills are to the surface of the body, numerous 
strong, and pointed papillae, imbricated on each other in a direc- 
tion from the top to the base of the organ. These papillae or ap- 
pendages have long been considered as only an extension of the 
sensitive surface, like the convolutions of the ethmoid and turbi- 
nated bones of the nose ; and thus affording a larger expanse and 
more numerous points for the particles of a sapid body to make 
its impression on the terminations of the gustatory nervous fila- 
ments. Hence, the animals in whom these papillae are found 
most developed and most numerous were considered to possess an 
increased degree of taste. 
The general membrane on the dorsum of the organ is very 
dense, and almost cartilaginous: it extends from the epiglottis be- 
hind, forwards to the tip and sides ; where it passes downwards to 
invest the lower surface of the tip and sides, and to*become con- 
tinuous with the general buccal and gingival mucous membrane. 
In these latter positions it becomes much changed in structure, 
and presents only the usual characters of mucous membrane. In 
the dog, especially, it is thickest and densest along the mesial 
line, where there exists a distinct raphe running the entire length 
of the tongue, and dividing it into two symmetrical portions. This 
structure differs materially from the general investing membrane. 
When isolated from its surrounding tissues it appears in the form 
of a distinct and rounded or flattened cord, vulgarly called “ the 
worm of the tongue,” and designated by the Caldani the “ linea 
albescens*.” 
This “ linea albescens” arises posteriorly from the upper surface 
of the os hyoides — its body and spur-like process — and from the 
substance of the hyo-epiglottic ligament, of which it forms a part 
and portion, and with the function of which it is intimately asso- 
ciated. It extends forwards to the very tip of the organ, and 
forms an intimate bond of union between its two halves. Where 
it is in connexion with the body of the tongue it sends, laterally, 
minute thread-like filaments amongst the fibres of the lingualis 
and the other intrinsic set of muscles. Its upper surface is most 
intimately connected with, and forms a part of, the structure of 
the investing membrane ; and at that part which corresponds to 
the free and moveable tip, its inferior surface is only covered by 
the mucous membrane that forms the frsenum linguse. It is in 
this situation alone that the entire breadth of its structure can be 
most easily got at, and it was, therefore, that spot which was 
formerly selected for removing it, in the cruel, useless, and un- 
called-for operation of “ worming,” intended either as a cure of or 
a preventive for rabies contagiosa. 
* leones Anatomic*. VcMet. 1804. 
