152 
Facts bearing on the Structure and Arrangement of a 
Nervous Mechanism demonstrated in the Auricle of the 
Frog’s Heart. By Lionel S. Beale, M.B., F.R.S. ; 
Fellow of the Royal College of Physicians; Physician 
to King’s College Hospital ; Professor of Physiology in 
King’s College, London. With Plate XIII. 
The rhythmic contractions of a portion of the muscular 
tissue of the heart continue for some time after it has been 
severed from the rest of the organ and removed from the body. 
A closely allied fact is observed in the case of the muscular 
coat of the intestinal canal ; and in some muscles of insect 
larvae, which have been removed from the body with due care, 
the muscular tissue continues to contract for some time after its 
removal. The muscles of the common maggot will retain 
their contractility for an hour or more after they have been 
placed upon a glass slide (“ Croonian Lecture,” ‘ Proceedings 
of Royal Society,’ May 11, 1865, p. 229). 
In all these instances careful observation will prove, not 
only that nerves have been removed with the contracting 
tissue, but that nerve-ganglia, or nerve-ganglion-cells, the 
centres with which the nerves are connected, are intact. 
The movements observed may, therefore, he dependent upon 
the action of the ganglion-cells. Pieces of muscle entirely 
separated from the nerve-cells cease to contract very soon after 
their removal, while, as is well known, if pieces of the 
ventricle of the heart of a frog, in which ganglia are knoivn 
to be situated, be removed, rhythmic contractions continue to 
take place for some time, but if those parts of the ventricle 
which are destitute of ganglia be selected, the incisions made 
are sufficient to stop rhythmic movements. 
If, then, we could demonstrate the distribution and arrange- 
ment of the nerves amongst the muscular fibres of the heart, 
and trace them to and from the ganglion-cells with which 
they are connected, we might, perhaps, be able to form some 
notion of the general arrangement of the nervous mechanism 
concerned in reflex movements ; and the conclusions arrived 
at might he of the greatest assistance in enabling us to trace 
out the changes which are essential to the simplest kinds of 
nervous action. 
The inquiry is, however, one of great practical difficulty, 
since it would be useless to attempt to follow a nerve, or even 
a bundle of nerves in their ramifications amongst the mus- 
