57 
probable Action in Health ancl Disease. 
any rate, upon tlie tongue of the frog are very highly elaborate 
nerve organs of a special structure, and having a very large number 
of nerve fibres distributed over a small space quite at the summit of 
the papilla.* If the frog possesses the sense of taste, the delicate 
papillae above referred to are doubtless the organs concerned, and 
not the general surface of the palate. 
But the nerve fibres near the capillary vessels may take part in 
general sensation. Doubtless it is through the agency of the beautiful 
little “ tactile corpuscles ” in the papillae of the skin that we are 
able to distinguish those very slight differences of quality in fabrics 
when the tip of the finger is gently drawn across them. But if 
every tactile corpuscle were destroyed, we should still be able to 
feel , and the skin of the finger would still be differently acted upon 
by hot things and cold things. According to the same reasoning, 
we are justified in supposing that the nerves which I have shown 
are distributed to the capillaries of voluntary muscle, act as sensi- 
tive fibres, and are perhaps concerned in conveying to us the 
sensation by which we are enabled to form a conception of the exact 
degree of contraction which has been effected in the muscle under 
different circumstances. And in certain forms of disease in which 
there is no loss in the power of contracting the muscle, but in which 
the mind does not form an accurate idea of the degree of contraction 
which has been induced, it is probable that these nerve fibres, or the 
centres with which they are connected, are the particular parts of 
the nervous system which are involved. The cold feeling, the chill 
which precedes a cold or an attack of fever, results, I believe, from a 
change effected in these fibres distributed to the capillaries, caused 
probably by disturbance in the capillary circulation and the conse- 
quent phenomena induced immediately outside the minute vessels. 
Few questions are of higher importance than the determination 
of the relationship of the nerves distributed to the capillaries to 
those ramifying in such great number on and amongst the muscular 
fibre cells of the small arteries which divide into branches from 
which the capillary vessels spring. I can adduce direct anatomical 
observations in favour of the view which I have been led to accept. 
In the frog I have succeeded in actually tracing nerve fibres from a 
ganglion to a nerve trunk, and from the trunk to the capillary 
vessels ; and in the bladder of the frog I have been able to follow 
fine nerve fibres from the ganglion both to arteries and capillary 
vessels. It is surely justifiable to infer that a similar disposition 
exists in the higher vertebrata and in man. But such an inference 
is almost irresistible if we bear in mind the vast number of ganglia 
existing in the submucous areolar tissue of the intestinal canal and 
the course taken by the nerve fibres from these, and the fact of the 
great alteration frequently taking place in the vascular turgescence 
* See ‘ Phil. Trans 1864. 
