TO THE ELEMENTAET FIBEES OF STEIPED MUSCLE. 
903 
my specimens, that the appearances represented in the drawings accompanying this 
paper are incompatible with the conclusion that all the fiae fibres I have described are 
merely fibres of connective tissue. 
Since it has been shown that many of the corpuscles in the connective tissue between 
the muscular fibres, and in other situations which are usually considered to be connective- 
tissue corpuscles, are reaUy connected with the nerve-fibres, and that the quantity of the 
connective tissue increases as the muscle advances in age, it remains for those who still 
maintain that this indefinite connective tissue is a structure developed specially for the 
support or nutrition of higher tissues, to explain, according to their view, its absence 
when the tissues are undergoing most active changes, during development, and when 
they are softest and therefore are in greater need of support, and how and at what 
period it comes into relation with the nerve-fibres, — why it is more abundant on the 
muscles of the tongue and diaphragm of the mouse than on the muscles of the limbs, — 
and many other facts which I have considered elsewhere, and which appear to me to be 
not only strongly opposed to this view of the origin of this form of connective tissue, but 
incompatible with it*. 
In adult animals the connective tissue is too thick to permit our seeing the arrange- 
ment of the very much more delicate'nervous structm’e beneath it ; and the difficulty is 
further increased by the chcumstance that the hght must first traverse the muscular fibre 
itself. The relation of the nerves to the sarcolemma remains constant ; but the connective 
tissue exists in greater quantity and is firmer and more fibrous hi old than in young 
muscles, and forms a fibrous stratum external to the nerve-fibres. If we attempt to tear 
off this connective tissue in order to see the nerve-fibres beneath it more distinctly, we 
almost invariably tear away the neiwes and vessels also ; for these structures are undoubt- 
edly connected with the connective tissue. 
It seems to me that many of the appearances observed receive at least a partial 
explanation from the following considerations. The muscle grows, gradually, until it 
attains perhaps twenty times the size it exhibited in the young frog. That part of the 
nerve-fibre which in the young animal might be said to be terminal, would in the larger 
muscle con’espond to trunks from which branches were given off in different directions ; 
and fibres and nuclei which were in contact with the muscular fibres would be removed, 
as the muscle grew, further and further away from the sarcolemma, but they would still 
be connected with the new fibres and nuclei which are developed just external to this 
membrane. Thus we should have a quantity of tissue composed of modified nuclei and 
wasted nerve-fibres which would accumulate as the muscle advanced in growth, and 
through which many of the neiwe-fibres would be seen to pass. Many of these nuclei 
and fibres having been originally continuous with the nerve-fibres would still retain 
connexion with them, but this connexion is not necessarily a physiological one. 
Other explanations might be offered, but I desire now only to draw attention to The 
fact that all nerve-fibres at their periphery are continuous with exceedingly delicate 
* “ The Structure of the Simple Tissues,” Lectures YI. and VII. 
