138 [June 19, 



Fine nerve-fibres run in the same sheath, with the dark-bordered 

 fibres. Some of these fibres are the direct continuation of dark- 

 bordered fibres. There are often also fine fibres to be demonstrated 

 external to what appears to be the sheath of the fibre. Nuclei 

 are connected with the dark-bordered fibre, with the fine fibres in, 

 and with those external to the sheath. The pale fibres of Kiihne 

 and Kolliker are always compound, and consist of 



1 . A very fine fibre prolonged from the dark-bordered fibre. 



2. Very fine fibres continuous with those in the sheath of the 

 nerves, or external to it. 



The author concludes, from numerous observations upon the 

 distribution of nerves in many different tissues, that the general 

 disposition of the finest fibres is the same as that of the coarser 

 trunks and fibres. In passing from the trunks towards the ultimate 

 distribution of the nerves, it might be said we meet with finer and 

 still finer networks and plexuses ; the finest fibres visible with the 

 highest powers (1700 diameters) being composed of more than a 

 single fibre. It is therefore probable that in all cases complete cir- 

 cuits exist. The author maintains that the really important part of 

 the peripheral nerve-fibres only commences at the point where the 

 dark-bordered nerve-fibre seems to cease. Beyond this there is a 

 most elaborate network, the fibres of which are compound and com- 

 posed of very fine fibres. The meshes of this network and the fibres 

 differ much in size in different tissues. The active elements of the 

 tissues lie in or upon the meshes of this network. 



The author then discusses the relation of the terminal branches of 

 the nerve-fibres to connective tissue. His views are briefly expressed 

 in the conclusions given below. In order to see the appearances 

 described by the author, the tissue must be mounted in some fluid 

 which reflects highly, like syrup or glycerine. The fine fibres he 

 has seen cannot be demonstrated in specimens mounted in fluids 

 composed mainly of water. 



The paper is accompanied with upwards of forty figures copied 

 from specimens magnified by a twelfth or by a twenty-sixth of an 

 inch object-glass made by Messrs. Powell and Lealand, and magni- 

 fying respectively 700 and 1 700 diameters linear. 



