286 Dr. Waller's Microscopic Examination of the 



The fungiform papillae do not generally project upwards, 

 but consist of a circular area containing a vascular coil and 

 surrounded by an elevated rim of the mucous membrane. 

 Scales of epithelium cover the papillae conicae, but the mucous 

 membrane is generally too opake to admit of the circulation of 

 the blood being clearly distinguished, except at the neuro- 

 vascular papillae, where it is seen in the coil and at numerous 

 spots about the size of j^o™"", where the mucous membrane 

 appears to be removed, so as to expose fully the capillary cir- 

 culation beneath. On these spots the forms of the ^blood- 

 globules are so distinct as to give the appearance of not being 

 confined in a vascular tube. The blood frequently stagnates 

 at these points, or bursts through and is effused in small 

 quantities over the papillary surface, where the separate glo- 

 bules may be seen to oscillate, evidently under the influence of 

 the cilia spread over the surface. In favourable cases nervous 

 filaments may be traced into the vascular area, similar to those 

 of the frog, forming a knot, which afterwards gives off' filaments 

 accompanying the vascular coil. 



These papillae and their nerves were most clearly displayed 

 in a toad not half-grown, which had been kept prisoner the 

 whole of the winter. From some accidental cause it had been 

 injured, which had produced great emaciation, and finally oc- 

 casioned its death. When examined life was extinct, but the 

 muscles were flaccid and circulation of blood existed in the 

 tongue. This organ was beautifully transparent; the papillae 

 conicae were as before described ; some of the neuro-vascular 

 papillae had a circular area with coils; others, mostly confined 

 to the extremity of the tongue, consisted of nearly globular 

 transparent vesicles, projecting above the membiane and con- 

 nected with it by a very narrow neck containing two capillary 

 vessels and a nerve. Near the point of insertion of the vesicle 

 to the membrane a nervous knot was seen, from whence nume- 

 rous nervous fibres proceeded up the pedicel into the vesicular 

 cavity. Numerous similar vesicles existed at the tubercles, 

 where they formed nearly a continuous row, the transparency 

 of the membrane allowing the nervous filaments which supplied 

 them to be traced backward to the main trunk, which they 

 joined at an acute angle. The vascular coil could likewise be 

 followed to similar venous and arterial trunks, closely accom- 

 panying the nerve. This beautiful arrangement may be aptly 

 compared to a bunch of currants, each currant representing a 

 vesicle with its internal coil, and its pedicel to the vasculo- 

 nervous neck of the papilla. As all the papillary nerves joined 

 the main trunk at acute angles, we may easily figure to our- 

 selves the appearance of the termination of the filaments of 

 the cranial nerve, as mentioned by Burdach, by stripping off 



