252 Dr. Beale Croonian Lecture. [May 11, 



their ultimate destination, there is at least a possibility, if not a reasonable 

 probability, that the ultimate arrangement of nerve-fibres in muscle, the 

 cornea, and other tissues is, in principle at least, the same. It may be 

 remarked, further, that it is not likely that the nerve-current would be 

 running iu the same direction in two distinct fibres situated close together, 

 while the existing anatomical arrangement above referred to is suggestive 

 of currents passing in opposite directions. This view is favoured by the 

 fact of one fibre being much finer than the other an arrangement which 

 would be fully explained if each of the two fibres were a part of two dif- 

 ferent circuits. My meaning will be understood at once if this diagram, 

 to which I now point, be examined. 



I have endeavoured to prove that in various forms of muscular tissue, 

 and in other textures, nothing but continuous nerve-fibres can be observed. 

 The most careful observation has failed to show any appearance which 

 could be considered as demonstrative of "ends" of any kind ; and although 

 in many cases I have been unable to follow the very fine fibres resulting 

 from the division of the nerve-fibres of one trunk into those of another 

 trunk although, therefore, there is, as it were, a hiatus in the evidence ad- 

 vanced in favour of this view being universally applicable, the appearances in 

 every one of the cases that I have examined are such as to render it almost 

 certain that this is the real arrangement. If we find a compound nerve- 

 trunk passing to one part of a muscle and another compound trunk passing 

 away from another part of the muscle, in such manner as would be easily 

 explained upon the supposition that certain of the fibres of one cord were 

 continuous with those of the other more especially if the action of these 

 fibres could be explained upon such an hypothesis, we should surely be 

 justified in inferring the continuity of the fibres, although we could not 

 trace them through their entire course. It might be urged by an objector, 

 that it is just at this intermediate point in many instances that the evidence 

 fails. But it must be borne in mind that it fails in certain instances only ; 

 for I have traced and can demonstrate, in some of my specimens, the nerve- 

 fibres distributed to muscular tissue in every part of their course. The 

 truth of my statements upon this anatomical question is in fact admitted in 

 the case of certain muscles ; and those who still maintain that nerve-fibres 

 "end" in voluntary muscle must maintain that there are some muscles 

 in which nerves form networks, while in others they terminate in distinct 

 ends that in fact nerve-fibres are distributed to different kinds of mus- 

 cular tissue upon at least two very distinct principles, although no dif- 

 ferences whatever can be shown in the essential structure or action either 

 of the muscular or of the nervous tissue. 



But the case is still stronger than this. I shall adduce a considerable 

 amount of collateral evidence in favour of the view that nerves form con- 

 tinuous and uninterrupted cords ; and this evidence will be derived from 

 many different sources. 



A.S there is the greatest difference of opinion with regard to the arrange- 



