1865.] Of the Terminal Networks and Plexuses. 253 



merit of the nerves in muscle, and as the question is now much involved, 

 it seems to me of the utmost importance to consider it from a general point 

 of view. Every careful examination that I have made with the view of 

 ascertaining the arrangement of the nerve-fibres in various tissues has 

 tended to confirm me in the opinion that networks and continuous circuits 

 exist, and that there are no " ends " or " terminal extremities." Although 

 I am of course ready to admit that no amount of argument from general 

 considerations can upset the conclusions resulting from direct observation 

 in special cases, I submit that the conclusions of my opponents, in the 

 particular instances advanced by them, have never been supported by posi- 

 tive demonstration. Indications of the appearances they have described un- 

 doubtedly exist ; but it seems very difficult to prepare specimens which shall 

 admit of but one interpretation, and so distinct that several independent 

 observers would, upon examination, arrive at one and the same conclusion. 

 It is too often urged that the specimens demonstrating " ends " and " end- 

 organs " do not " keep," and must be examined when quite fresh, while 

 I find no difficulty in preserving those which demonstrate " networks " and 

 " plexuses." I desire, however, to weigh carefully every kind of evidence 

 that can be brought to bear upon the determination of this point, which is 

 undoubtedly one of very great difficulty. As the question, too, is a funda- 

 mental one of the utmost importance, it is worthy of the most patient 

 consideration. 



Of terminal plexuses and networks of fine nerve-fibres in the cornea and 

 in connective tissue. 



From its transparency, the simplicity of its structure, and the absence 

 of vessels over at least a great part of its extent, the cornea of the smaller 

 lower animals presents many advantages for studying the arrangement of 

 the ultimate nerve-fibres. My friend and former pupil, Prof. Ciaccio, now 

 of Naples, very carefully studied this subject ; and the results of his obser- 

 vations will be found in the Transactions of the Microscopical Society for 

 July 1863, "On the Nerves of the Cornea, and of their distribution in the 

 Corneal Tissue of Man and Animals," by Prof. G. V. Ciaccio, M.D., of 

 Naples. Of the existence of nerve-networks in this tissue there can be 

 no question ; but there is some difference of opinion regarding the manner 

 in which the ultimate nerve-fibres are arranged. This drawing represents 

 the nerve-fibres in the cornea of the Hyla. The relation of the finest 

 nerve-fibres to the corneal corpuscles is a question of great importance. 

 Kuhne has endeavoured to prove that the ultimate nerve-fibres are con- 

 tinuous with the processes of the connective-tissue-corpuscles, and that 

 there is an actual continuity of tissue, such as he believes exists between 

 the nerve-fibre which perforates the sarcolemma of muscle and the pro- 

 toplasmic matter which is in actual contact with the contractile tissue. 



Careful observation, with the aid of the -^ and -^-object-glasses, has 

 convinced me that there is no such arrangement as Kiihne supposes, but 



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