I 
bodies, which compose the mass in which nerves terminate, 
are actual epithelial cells. 
In the simple papillae (PL I, fig. 1, d) of the frog’s 
tongue, a “ nucleus ” of a nerve sometimes projects beyond 
the outline of the papilla and lies amongst the epithelium. 
This nucleus, however, adheres to the papilla when all the 
epithelial cells have been detached. It might from its posi- 
tion be easily mistaken for an epithelial cell, but it is no 
more really related to this structure than is a ganglion-cell, 
or a caudate nerve-cell of the spinal cord. The cells of the 
ciliated epithelium of the frog’s tongue are not in any in- 
stance, as far as I am able to observe, connected with the 
nerve-fibres. It is probable that the opposite inference, 
which is still held by many observers, has resulted from the 
observation of such a nucleus as is represented in PI. I, 
fig. 1, d, projecting beyond and adherent to the surface of 
the papilla. It is really continuous with the delicate nerve- 
fibres (e) ramifying in the substance of the papilla, but it is 
not an epithelial cell, and remains adherent after every par- 
ticle of epithelium has been removed. 
More recently, the view that the finest ramifications of 
the nerve-fibres run amongst the epithelial cells of various 
tissues has been gaining ground, but it is probable this 
will turn out incorrect. 
The nervous tissue is in all cases structurally distinct from 
every other tissue, in every part of its distribution. It never 
blends with epithelium any more than it blends with fibrous 
tissue, cartilage, bone, or muscle. If nerves exert any direct 
influence upon the nutrition of any of these tissues, the in- 
fluence must be exerted through some distance. The results 
of anatomical research render any physiological doctrine 
which maintains that nerves act through their structural 
continuity with other tissues untenable. My own observa- 
tions lead me to conclude that nerves do not directly influence 
the processes of nutrition, growth, or development at all. 
They act only indirectly, and affect the supply of nutrient 
matter distributed, by modifying the calibre of the vessels, 
and hence regulate the supply of blood which passes to the 
capillaries. The nerves, I believe, really exert their in- 
fluence upon the contractile muscular coat of the small 
arteries and veins alone, and do not act directly upon any 
other tissues. 
The Nerves. 
With regard to the trunks of the nerves, I remark the fol- 
lowing facts of importance : 
