13 
very same set of central cells as that from which the vaso- 
motor fibres take their rise. It is through these fibres that 
changes in the nutrition of the tissues may affect the circula- 
tion in the neighbouring vessels. 
In these fungiform papillae, then, there are — 
1. The bundle of nerve-fibres which is distributed to the 
sensitive nervous organ at the summit. 
2. Delicate fibres which may be traced to fibres running in 
the same bundles as purely sensitive fibres. These delicate 
fibres are distributed — 
a. Around the capillaries of the papilla (PI. I, fig. 1, i). 
See also PI. Ill, fig. 15. 
b. Some fibres ramify in the connective tissue of the 
simple papillae (PI. I, fig. 1). 
c. Some are distributed to the muscular fibres (figs. 1 
& 9). 
Now, the first and second fibres are probably sensitive, 
excitor, or afferent, whilst the last must be motor. From this 
observation it follows that certain afferent and motor fibres 
are intimately related at their distribution, a conclusion 
already arrived at in my investigations upon the distribution 
of the nerves to the frog’s bladder, the palate, and pharynx. 
Moreover, I think that fibres passing from the plexus of sensi- 
tive fibres at the summit of the papilla, establish here and 
there a structural continuity between these and the fibres 
ramifying in the connective tissue and around the capillary 
vessels. It is very difficult to obtain a specimen which 
renders this perfectly certain, but I have been led to a similar 
conclusion in investigations upon the corpuscula tactus of the 
human subject. The physiological interest and importance of 
this branch of anatomical inquiry are so great, and it pro- 
mises to lead to such important results, that it cannot be too 
minutely or too patiently worked out. 
Of the Muscles. 
The muscular fibres of the papilla (PI. I, fig. 1, h ) are the 
continuations of muscular fibres in the substance of the 
tongue. They are excellent examples of branching striped 
muscle. The finest branches are less than 5 0 ‘ 0 0 th of an inch 
in diameter, but these exhibit the most distinct transverse 
markings. The markings, however, gradually cease, and the 
fibre becomes a mere line, which is lost in the connective 
tissue at the summit of the papilla. The arrangement will be 
understood if figs. 1 & 9 be referred to. 
The so-called nuclei or masses of germinal matter in con- 
