
1905. ] The Structure and Function of Nerve Fibres. 345 
Let us turn to the contracted states of muscle, in which it is known that 
coagulation has taken place—to “rigor mortis” and to “heat rigor.” Apply 
a load to muscle in either of these two conditions, and the contracted state is 
not increased, and why? Obviously because (1) the maximum coagulation 
has already taken place, and (2) because the membranes dividing the muscle- 
fibril and also the muscle-fibre into actual segmented parts have been 
injured. Remove these segmenting membranes and there can be no further 
contraction, since alternately arranged foci of high and low pressure can 
produce no externally felt alteration in the whole bulk of the muscle unless 
definitely separated from one another by partitions preserving their 
distribution. 
In muscle, therefore, we must raise to a high functional value the 
transecting membranes, which have no place in the function or structure of 
nerve except that of insulating each individual nerve-fibre. We must, 
therefore, when we come to study the effects produced in muscle by the 
transmission of an electrical current, expect to find the relative importance of 
true polarisation and “ pseudo-polarisation” changing places with one 
another. We must therefore also expect to find, in the case of muscle but 
not of nerve, an appearance of new chemical substances originating from the 
processes of hydrolysis taking place at veritable “poles” situated at frequent 
points within the continuity of the muscle-fibril. In fact in muscle, these 
processes of polarisation and hydrolysis are probably the servants of another 
useful purpose. The osmotic changes in nerve were self-annulling, the whole 
process admitted of a purely physical explanation. In muscle, as I have 
depicted it, the process is different in this particular. The conditions evoked 
by it are such as to ensure their own permanence. 
It is obvious that the difference must be so. Nerve isa material adapted 
for the transmission of energy from point to point. The external work done 
In nerve-conduction is infinitesimal. In muscle, the performance of external 
work is the main duty of the tissue. A transmitted excitation proceeding 
along a muscle-fibril with an inhibition in its wake would be valueless, or of 
value only as secondarily exciting to some other consequence. Such a 
phenomenon might be supposed to occur in the sarcoplasm, provided that a 
phenomenon of another kind took place in the sarcostyles. 
This being the case, it is necessary to provide some factor other than this 
which shall secure the relaxation of a muscle following upon a sustained 
contraction. Conceivably this factor is to be found in the internal true 
polarisation taking place in every segment of the muscle-fibril; the separation 
of alkali at one pole and acid at another. The further removal of acid out of 
the muscle may also be conceived to serve some functional end. Thus in 
VOL. LXXVI.—B, titan 
