450 
PROFESSOR BEALE’S NEW OBSERVATIONS UPON THE 
tinuity of tissue to the bundle of nerve-fibres in the body of the papilla. These peculiar 
cells in the summit of the papilla cannot therefore be regarded as epithelium, and the 
mass constitutes a peculiar organ which belongs not to epithelial structures, but to the 
nervous system. 
Although there can be no doubt whatever as to the existence of an intricate and 
exceedingly delicate nervous network or plexus at the summit of every papilla, such 
a plexus might be connected with the nerves according to one of two very different 
arrangements : — 
1. The plexus might be formed at the extremity of a nerve or nerves, as represented 
in diagram (Plate XXII. fig. 17). 
2. The plexus might form a part of the course of a nerve or nerves, as represented in 
diagram (Plate XXII. fig. 18). 
If the first be true, the network must be terminal, and impressions must be conveyed 
along the fibre, of which the plexus is but the terminal expansion, direct from peri- 
phery to centre. If the second arrangement is correct, the network forms a part of a 
continuous circuit or of continuous circuits. I believe the division of the nerves at the 
base of the papilla, already adverted to, is alone sufficient to justify us in accepting the 
second conclusion as the more probable ; but when this fact is considered with reference 
to those which I have adduced in my paper published in the ‘ Transactions ’ for 1863, 
and that in the ‘Proceedings’ for June 1864, and the observations published in several 
papers in vols. ii., iii., and iv. of my ‘Archives,’ and in the Croonian Lecture for 1865, 
I think the general view in favour of complete circuits is the only one which the anato- 
mical facts render tenable. The mode of branching and division of trunks and individual 
fibres is represented in Plate XXII. figs. 20, 21, 22, 23. 
From the number and size of the nerve-fibres constituting the bundle in the centre of 
the papilla, we should infer that the finest ramifications resulting from the subdivision 
of these branches would be very numerous, since it has been shown that the fine fibres 
resulting from the subdivision of a single dark-bordered fibre in the frog’s bladder, 
palate, skin, and muscle, constitute plexuses or networks which pass over a very extended 
area. The mode of formation of a nerve-plexus is represented in Plate XXII. figs. 11 
& 14. In these beautiful little organs the numerous fibres resulting from the sub- 
division of the dark-bordered fibres are distributed over a comparatively small extent 
of tissue, forming the summit of the papilla. Still we have the same formation of 
plexuses, the constant change in the direction taken by fibres, and the same crossing 
and intercrossing which have been noticed in other situations. In fact the nervous 
distribution in these organs presents the same typical arrangement as is met with in 
other tissues, but it is compressed into a very small space. 
Now with regard to the epithelium-like structure upon the summit, it has been 
shown that the nerve-fibres are probably continuous with the material lying between 
the large nuclei. In fact if the interpretation of the appearances which I have given 
be correct, the arrangement may be expressed thus :■ — 
