( 5.3 ) 
II. — The Nerves of Capillary Vessels and their probable Action 
in Health and Disease. By Dr. Lionel S. Beale, F.B.S., 
Fellow of the Koyal College of Physicians ; Physician to King’s 
College Hospital. 
( Conclusion of a Paper commenced in the January Number of the Journal .) 
Part II. — Physiological and Pathological. 
Considering the arrangement of nerve fibres in the organs of sense, 
no one would be likely to conclude that those distributed to capillary 
vessels were in any way concerned in special sensation. We know 
that many of the ultimate parts of organs which take part in sen- 
sation — which indeed constitute the active portion of the sensitive 
apparatus, are destitute of vessels altogether. These and other 
considerations render it certain that the nerve fibres of the capil- 
laries are not nerves of special sense. 
The capillaries are not provided with muscular fibres, nor is 
there any contractile tissue to be demonstrated in connection with 
them. Although it has been confidently asserted that the capillary 
walls consist of protoplasm (!), anyone who will be at the pains of 
examining actual capillaries, as, for example, those of the pia mater, 
will soon be convinced that this view is a mistake. It is, in fact, one 
of those conjectural anatomical observations which are in favour 
in these days. An hypothesis was advanced to account for the 
passage of blood corpuscles through the capillary walls, but before 
this hypothesis could be received it was necessary that some one 
should demonstrate the protoplasmic character of the capillary walls. 
Protoplasm was therefore conjecturally discovered in the capillaries 
by more than one microscopical philosopher. 
The walls of capillaries may be well studied in the capillary 
vessels of the ciliary processes of the eye. The membrane of which 
they consist can be seen, and the bioplasts connected with it demon- 
strated in considerable number, and without difficulty. The mem- 
brane is transparent, slightly fibrous in the vessels of old animals, 
highly elastic, but destitute of any structure that can be regarded 
as contractile. The capillaries torn from the grey matter of the 
brain and those of the choroid plexus are also favourable for investi- 
gation. We may therefore, I think, dismiss the idea that these nerve 
fibres are motor, or are in any way concerned directly, — that is, by 
any influence exerted by them on the walls of the capillaries, in re- 
ducing the calibre of these minute vessels. If protoplasm could 
only be proved to exist in the walls of the capillaries, the presence 
and action of the nerve fibres would be accounted for. They would 
cause the protoplasmic substance to contract. But as the capillary 
