56 The Nerves of Capillary Vessels and their 
parietes are not composed of protoplasm, but consist of a passive 
permeable membrane, such an explanation is inadmissible. 
Next, I must ask the reader to consider with me whether it is 
probable that these nerves are connected with nutritive or secretory 
operations. Now, although many high authorities still hold to the 
opinion that nerves do act directly upon the nutritive process, many 
considerations render it at least doubtful whether the action of cells 
is directly influenced by nerve fibres in any case. Nutrition and 
growth are carried on at a rapid rate in living structures which are 
destitute of nerves, and at every period of life. In disease the most 
active nutritive changes occur in tissues which appear to be wanting 
in nerve fibres. For example, the formation of pus from epithelium 
and the formation of tubercle, can hardly be attributed to the in- 
fluence exerted by nerves, seeing that the phenomena occur in parts 
to which nerve fibres do not reach. Nutrition and growth are 
most active in all living beings at a period of development anterior 
to that when nerves are formed. Secretion is very active in glands 
which receive a limited supply of nerves, and in those parts of glands 
to which very few nerves are distributed. Contrast, for example, 
the multitudes of fine nerve fibres distributed to the surface of a 
sensitive mucous membrane, with the few that can be traced around 
the uriniferous tube, or followed to the follicles of the sebaceous 
glands, or to those of the salivary glands. Pfluger’s statements on 
this point have not been confirmed by other observers, and from my 
own observations I am convinced that if, as Pfluger asserts, nerve 
fibres are distributed to secreting cells, they are arranged in a 
manner very different from that represented by him in his drawings, 
and the character of the fibres is different. In those cases in which 
nerves can be followed near to secreting cells, it is more probable 
that their function is afferent as regards the nerve centre govern- 
ing the nearest vessels, than that they are directly concerned in the 
actual secerning process. This I believe to be due rather to the 
properties and powers of the bioplasm of the cell, than to any mys- 
terious, and at this time purely conjectural, influence of nerve force. 
What, then, is the probable office of the nerve fibres which are 
so freely distributed to many of the capillary vessels ? Upon many 
sensitive surfaces the fine nerve fibres running very close to the 
capillaries are indeed so numerous that we can hardly avoid coming 
to the conclusion that these very nerve fibres must be concerned in 
sensation. The capillaries of the mucous membrane of the frog’s 
palate, for example, are surrounded by a complete network of very 
delicate nerve fibres, which lie immediately beneath the epithelium. 
In this situation there are no papillae , nor is there any form of 
special sense organ to which nerves are distributed. By experi- 
ment we know that this surface is eminently sensitive, though there 
is no reason to think that it is concerned in the sense of taste. At 
