898 
PBOEESSOE BEALE ON THE DISTEIBUTION OE NEEVES 
becomes quite distinct. As I have succeeded in following very fine compound fibres for 
a considerable distance as they passed amongst several adjacent muscular fibres, I feel 
satisfied that many apparent ends result from the fibres becoming too delicate to be fol- 
lowed beyond this point. Very slight pressure of the thin glass renders even dark-bor- 
dered fibres quite invisible ; and very moderate stretching renders undoubted nerve-fibres 
so very fine that they cannot be seen, or, if they remain visible, all characters which 
would enable us to identify them as nerve-fibres are completely lost. But even if no 
such .appearances as those I have just referred to existed, it would be more in accordance 
with what we have learnt from many investigations, to conclude that the fibres really 
extend further than we are able to follow them, than to assume that they absolutely 
cease at the point at which, having very gradually become finer and finer, they are no 
longer visible to us. Moreover, as I have already stated, dark-bordered fibres are to be 
demonstrated in all parts of the muscular fibre, even upon the tendon near its connexion 
with the muscular fibres. It is hardly likely that this distribution of coarse fibres OTer 
the general surface of the muscles should be associated with a very partial and unequal 
distribution of the fine fibres which result from their division. As the broad pale fibres 
described by Kuhne are really composed of several fine fibres (Plates XLII. & XLIII. 
figs. 14, 16, 18, & 20), which are often connected by transverse branches so as to form a 
network, and as the fine compound fibres gradually become finer and finer until they 
cease to be visible, it is still more improbable that what appeared to him and Kollikes 
to be ends should be real natural terminations, than if the arrangement had been as 
Kuhne has described it. It seems therefore to me that the only inference which c-an be 
diuwn from the facts demonstrated is, that the nerves terminate in a network : but there 
are still two modes of arrangement possible with regard to the distribution of this network. 
1. It may be confined to one part of the muscular fibre. 
2. It may extend down the fibre throughout its entire length. 
It is true that the network (Plate XLII. figs. 13, 14) which is so readily demonstrable 
near the plexus of the dark-bordered fibres very soon becomes so faint as to be lost. The 
meshes are smaller near the large branches of nerve-fibres than further away, and it is at 
this point that the rupture of the fibres takes place when the muscle is caused to contract 
violently soon after death. There is therefore no doubt that the fibres of the pectoral 
muscle receive a greater supply of nerve-fibres near their central part than nearer their 
extremities ; but it is quite certain that the supply of nerve-fibres is not limited to this 
portion of the muscle. 
Although I have never been able to demonstrate uninterruptedly the fibres of such a 
network over more than the y^th of an inch of a fully-formed fibre of the breast-muscle 
of the frog, I have succeeded in doing so several times in the case of fibres undergoing 
development, and about the ^ - do oth of an inch in diameter (Plate XLIV. fig. 30). Upon 
these I have seen such a network, and I consider that the evidence in favour of the 
existence of a network extending from one end to the other of the muscular fibre ot 
the voluntary muscle of the frog, though by no means equally distributed over every part 
