AND NERVES OF THE TONGUE OF THE FROG AND TOAD. 
147 
which surround the nervous extremities in all directions. We find also a zone or 
belt which encircles the gustatory area, and serves principally to protect and support 
it. Numerous muscular fibres are directed towards this zone, which will account 
for the partial erectility of the fungiform papillae on certain occasions. 
The gustatory area is placed sometimes at the extremity, at others at the sides of 
the papillae. Whether this difference in situation be connected or not with any 
difference of sensation, it is impossible to determine ; but in each case the gustatory 
area is placed conveniently near to any liquid spread over the tongue. It is further 
observed that the height of these papillae varies with that of the surrounding papillae 
conicae. We are well-aware that it is only when in solution bodies can be tasted. 
The trituration of substances in the mouth has the effect of producing this wherever 
it is possible. When once in this condition, we cannot but admire the beautiful and 
simple structural arrangement by which taste is effected. The membrane of the gus- 
tatory area is so exceedingly thin that the transudation of any liquid in contact with 
it must be proportionately rapid. Accordingly, the open extremities of the nerves 
may be considered as immersed into the solution which it has to analyse, whether to 
reject, or to allow to pass on to the stomach. The mysterious action by which the 
material world comes in contact with mind, is being effected under our closest 
scrutiny. If we are ever to penetrate further into the arcana of life, may we not 
expect to do so by observing these phenomena while the vital powers are intact ? 
While the nerve is being stimulated, the current within the capillary coil is continuing 
its course, and it requires but a slight acquaintance with the laws of imbibition to 
recognize that in this case the sapid solution must be rapidly eliminated, and that 
the nerve will consequently be free from its presence, and fresh to receive a new 
impression. 
Tongue of the Toad. 
Unlike what might have been expected from the habits of this animal, its organ of 
taste is less developed than that of the frog. The tongue is of a similar structure 
and form, and is covered with papillae more minute and simple. The fungiform 
papillae are less numerous. In the full-grown animal they present at their summit a 
circular capillary enclosing a fasciculus of nerve-tubes closely joined together. They 
also contain muscular fibres, and are provided with cilia. 
The conical papillae are less distinct, and are composed rather of folds or rugae of 
the membrane than of separate bodies. On comparing a frog and toad of the same 
size, we find in the latter the papillae much less developed. Taking, for example, a 
toad weighing five drachms, we find the epithelian scales over the dorsum very 
indistinct, and the surface finely granular. The fungiform papillae are the 3-g-oth of 
an inch in thickness, without any pedicel. The blood-vessels form two or three loops 
at the summit of the papilla. The nerve-tubules are much less numerous than those 
of the frog, less distinct and extremely varicose. The summit of the papilla consists 
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