456 NOTES AND MEMORANDA. 



are largest at the bifurcations of medium-sized nerves or at 

 the junction of these with collateral branches, smallest at the 

 points of divisions of the largest nerves, though the nuclei 

 are, as a rule, most evident here. 



Lastly, the terminal bifurcations possess corpuscles of 

 moderate size, and some of these have peculiar characters. 



Instead of a granular mass, coloured brown by osmic acid, 

 one sees a triangular element with fine granulation, in which 

 neither nucleus nor nucleolus can be distinguished. Osmic 

 acid imparts a pale-brown colour to these. 



The nuclear bodies in the course of the nerve-fibres or 

 " parietal nuclei" are never found opposite the point of 

 bifurcation or where the nerve is joined by a collateral branch. 

 They are always distintly elliptical. Their long axis is 

 parallel to the axis of the nerve, and measures, as a rule, 

 from 15 to 20 mm., the short axis about 5 to 8 mm. 



The substance of the nuclei is finely granular, and some- 

 times the extremities of the long axes of these bodies have a 

 similar appearance. Nucleoli are seen here also. 



In the course of the finest nerves and of those of a medium 

 size are seen bodies, less regularly elliptical than the above, 

 less granular, and without nucleoli. 



As the fine nerve-ramifications divide they acquire nume- 

 rous anastomoses and form plexuses. The nodal points of 

 these plexuses are occupied by granular nucleated proto- 

 plasmic masses, quite similar to those found at the points of 

 bifurcation. 



At the points where several fibres communicate there are 

 seen regular branched cells like multipolar ganglion cells. 



Leboucq regards the embryonic nerves, i. e. the principal 

 trunks, as being formed of bundles of primitive fibrils in the 

 sense attached to them by Max Schultze. Where bundles 

 divide they split up in such a way that the ultimate rami- 

 fications are formed by the free primitive fibrils. 



The fibrils are bound together by a granular cement-sub- 

 stance, which is most marked at the points of bifurcation. 

 At such a point the granular mass of protoplasm is nucleated, 

 and represents a cellular element lying on a bundle of fibrils. 

 From this fact he draws some deductions later on. Although 

 he was unable to demonstrate the existence of a Schwann's 

 sheath in bundles of a certain size, Leboucq still considers 

 that it is probably present. He holds that Max Schultze's 

 scheme of the structure of nerve-fibres holds good for 

 embryonic nerves also. 



The primitive fibril is the fundamental element. One 

 nerve differs from another in the quantity of elements united 



